# Make Konsole follow Plasma's light/dark color scheme

> Turn on Konsole's built-in light/dark profile sync, add a light twin of your dark profile, and test both directions with a live Plasma scheme switch.

Published 2026-10-13. HTML version: https://guides.tsvinc.dev/konsole-follow-plasma-light-dark/


Make Konsole switch its windows between a light and a dark profile whenever Plasma's color scheme changes, open windows included, using the profile sync that Konsole 26.08 ships switched off.

> **Scope** — Verified on: Fedora 44 desktop, KDE Plasma 6.7.5 on X11, Konsole 26.08.1, kf6-kconfig 6.31.0, Qt 6.11.2 (2026-10-25).
> **Not verified:** Plasma's own scheduled switch (`AutomaticLookAndFeel`) driving Konsole; I only watched scheme changes I triggered with step 5's commands. A new window opened while Plasma is light, and new tabs: the light-mode windows I tested that day all predate the light profile (Field notes). Starting the test in light mode. The settings-dialog route (Notes). A bundled light scheme such as `SolarizedLight`; I used my own. Whether a Konsole process that was already running picks up step 3. Wayland, other distributions, Konsole 26.08.0. The rollback on the live desktop (run on copies of the files only).
> **Needs:** Konsole 26.08.0 or newer; a Plasma 6 session; `kwriteconfig6` and `kreadconfig6` (Fedora package `kf6-kconfig`); `plasma-apply-colorscheme` (Fedora package `plasma-workspace`) for the test; a dark Konsole profile whose file has a `ColorScheme=` line; a light Konsole color scheme. Optional: `strings` (`binutils`) to list Konsole's bundled schemes; `xdotool` and ImageMagick to screenshot the test window.
> **Time:** 15 min. **Risk:** low. The setup is per user: `konsolerc` gains one group of three keys and one profile file is added. With the sync on, Konsole puts the light or dark profile on every tab of that Konsole process whenever a window opens and at each switch (step 3). The test in step 5 changes Plasma's color scheme for the whole session and leaves an extra `ColorScheme=` line in `~/.config/kdeglobals`; step 1 copies that file and step 6 puts it back. Plasma also rewrote its GTK and Qt theme files under `~/.config/` during my round trip (`gtk-3.0/`, `gtk-4.0/`, `gtkrc`, `gtkrc-2.0`, `xsettingsd/`, `dconf/user`, `Trolltech.conf`, all written at the second command); I didn't compare them before and after. Undo: delete the three keys and move the light profile out (Undo / rollback).

## Before you start

- Konsole is 26.08.0 or newer. That is the first stable release with the setting.
  ```console
  $ rpm -q konsole
  konsole-26.08.1-1.fc44.x86_64
  ```
  Expected: 26.08.0 or later. On other distributions, ask the package manager.
- The sync is still off, and you know which profile Konsole uses now:
  ```console
  $ kreadconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme

  $ kreadconfig6 --file konsolerc --group 'Desktop Entry' --key DefaultProfile
  user-default.profile
  $ kreadconfig6 --file kdeglobals --group KDE --key AutomaticLookAndFeel
  true
  ```
  Expected: an empty line for `SyncProfileWithSystemTheme` (unset, and off by default). `DefaultProfile` is the profile file new windows get today; mine is the dark one. `AutomaticLookAndFeel` is Plasma's own automatic light/dark switching. It was on here; Konsole reacts only to the color scheme, so the manual works without it by the source (not tried with it off).
- Your dark profile has a `ColorScheme=` line, and you have a light scheme:
  ```console
  $ cd ~/.local/share/konsole
  $ grep -H -e '^Name=' -e '^ColorScheme=' *.profile
  user-default.profile:ColorScheme=islands-dark
  user-default.profile:Name=user-default
  $ ls -1 *.colorscheme
  islands-dark.colorscheme
  islands-light.colorscheme
  ```
  Expected: the dark profile with its `Name=` and `ColorScheme=`. Step 2 assumes the file is named after the profile (`<Name>.profile`), as mine is. A scheme's name is its `.colorscheme` file name without the extension. A profile without a `ColorScheme=` line is not covered here.
- If you have no light scheme of your own: Konsole 26.08.1 builds its bundled schemes into its library (in the Fedora package `konsole-part`), and this lists them:
  ```console
  $ strings -e b /usr/lib64/libkonsoleprivate.so.* | grep '\.colorscheme$'
  *.colorscheme
  RedOnBlack.colorscheme
  BlueOnBlack.colorscheme
  Breeze.colorscheme
  GreenOnBlack.colorscheme
  Solarized.colorscheme
  SolarizedLight.colorscheme
  BlackOnWhite.colorscheme
  Campbell.colorscheme
  DarkPastels.colorscheme
  Linux.colorscheme
  BlackOnLightYellow.colorscheme
  WhiteOnBlack.colorscheme
  BlackOnRandomLight.colorscheme
  ```
  Expected: the bundled scheme names. The first line, `*.colorscheme`, is a file-name filter from Konsole's code, not a scheme. Going by their names, the light ones are `SolarizedLight`, `BlackOnWhite`, `BlackOnLightYellow` and `BlackOnRandomLight`. Konsole looks for `<name>.colorscheme` under `~/.local/share/konsole/` and the system data directories first, then in this bundle (source: `ColorSchemeManager.cpp`). Mine is `islands-light`, made from the light variant of my editor theme (Field notes); I haven't put a bundled one in a profile.
- Variables instead of placeholders: step 2 sets `DARK` (your dark profile's `Name=`), `LIGHT` (a name for the new light profile) and `LIGHT_SCHEME` (the light scheme's name). Steps 2 and 3, Verify and the undo use them; in a new shell, set them again. Step 5's screenshot method names `<PID>`, `<WINDOW_ID>` and `<FILE>`.

## Steps

1. **Back up `konsolerc`, `kdeglobals` and your profiles.**
   ```console
   $ mkdir -p ~/konsole-backup
   $ cp -p ~/.config/konsolerc ~/.config/kdeglobals ~/.local/share/konsole/*.profile ~/konsole-backup/
   $ ls -1 ~/konsole-backup
   kdeglobals
   konsolerc
   user-default.profile
   ```
   Expected: the two config files and every `.profile` file. `kdeglobals` is in the list because step 5 writes to it.
2. **Make a light twin of the dark profile.** Put your names in the second line (mine are shown), then copy the dark profile under the new name with the light scheme:
   ```console
   $ cd ~/.local/share/konsole
   $ DARK=user-default LIGHT=user-light LIGHT_SCHEME=islands-light
   $ sed -e "s/^Name=.*/Name=$LIGHT/" -e "s/^ColorScheme=.*/ColorScheme=$LIGHT_SCHEME/" "$DARK.profile" > "$LIGHT.profile"
   $ diff "$DARK.profile" "$LIGHT.profile"
   2c2
   < ColorScheme=islands-dark
   ---
   > ColorScheme=islands-light
   7c7
   < Name=user-default
   ---
   > Name=user-light
   ```
   Expected: exactly two lines differ, `ColorScheme=` and `Name=`. If `diff` shows only the `Name=` line, both profiles use the same scheme: Failure modes, row 2.
3. **Turn on the sync and name the two profiles.**
   ```console
   $ kwriteconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme true
   $ kwriteconfig6 --file konsolerc --group LightDarkTheme --key LightThemeProfile "$LIGHT"
   $ kwriteconfig6 --file konsolerc --group LightDarkTheme --key DarkThemeProfile "$DARK"
   $ kreadconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme
   true
   $ kreadconfig6 --file konsolerc --group LightDarkTheme --key LightThemeProfile
   user-light
   $ kreadconfig6 --file konsolerc --group LightDarkTheme --key DarkThemeProfile
   user-default
   ```
   Expected: `true`, then the light and the dark name, spelled exactly as the profiles' `Name=` lines. Konsole looks the profiles up by that name; a name that matches no profile gets Konsole's built-in profile instead, without a message (source: `ProfileManager.cpp`; not tried).

   > [!NOTE] Every tab gets the pair
   > Whenever a window opens and on each switch, Konsole sets the light or the dark profile on every session of that Konsole process, so a tab you opened with another profile changes to the pair too (source: `applyThemeProfile()` in `MainWindow.cpp`; not tried).
4. **Open a test window in a new Konsole process.**
   ```bash
   konsole --separate &
   ```
   Don't pass `--profile`: the sync has to choose the profile. `--separate` starts a new process, which reads `konsolerc` when it starts, even where Konsole is set to run all windows in one process (source: `main.cpp`; that option, `UseSingleInstance`, is off by default). To see the ANSI palette as well as the background, you can run this loop in the test window:
   ```bash
   for i in 0 1 2 3 4 5 6 7; do printf '\e[3%sm normal%s \e[9%sm bright%s \e[2;3%sm faint%s\e[0m\n' $i $i $i $i $i $i; done
   ```
   It comes from the script I used for one of that afternoon's light-mode screenshots (13:49). The live-switch window in Verify printed a single `color0`–`color7` row instead, with a command I didn't record.

   Expected: the colors of the profile for Plasma's current mode. Plasma was dark here and the window came up dark, background pixel 24,25,27.
5. **Switch Plasma to the other scheme and back while the test window is open.** First, the scheme the session is on:
   ```console
   $ kreadconfig6 --file kdeglobals --group General --key ColorScheme
   BreezeDark
   ```
   Expected: the current scheme's name. Here `~/.config/kdeglobals` itself has no `ColorScheme=` line; the value comes from `~/.config/kdedefaults/kdeglobals`, which is first in `XDG_CONFIG_DIRS` in my session. Switch to the other scheme first: by its source, `plasma-apply-colorscheme` given the scheme that is already set only reports that and changes nothing (not tried). Mine was `BreezeDark`, so:
   ```bash
   plasma-apply-colorscheme BreezeLight
   ```
   Wait about 4 s and look at the test window, then switch back:
   ```bash
   plasma-apply-colorscheme BreezeDark
   ```
   By its source (plasma-workspace 6.7.5), each successful call prints `Successfully applied the color scheme <name> to your current Plasma session`. Expected: the open window turns light, then dark again.

   Screenshots, for the screen half of Verify (optional): save the test window before the first command and about 4 s after each, as `~/konsole-test/1-dark-start.png`, `2-after-light.png` and `3-after-dark.png` (names for a start in dark mode; `mkdir -p ~/konsole-test` first). I found the window with `xdotool search --pid <PID> --onlyvisible`, where `<PID>` is the `konsole --separate` process (`$!` right after step 4), and saved it with ImageMagick's `import -window <WINDOW_ID> <FILE>`. The exact command lines weren't recorded, and my files went to a different directory; I copied them into `~/konsole-test/` for the re-run in Field notes.

   Run both directions. On my box a window that comes up dark proves little: `DefaultProfile` is my dark profile, so with the sync off a new window is dark in dark mode too. The switch to light shows that the sync works. The switch back shows that the dark profile is still dark; if both profiles carry the light scheme (Failure modes, row 2), a window in light mode looks right either way.

   These two scheme names are the only ones I tried. My session was dark, on the Breeze Dark global theme (`LookAndFeelPackage=org.kde.breezedark.desktop`), so the round trip ended in dark mode, where it started. If you start in light mode or on another scheme, end on the one you started from `[UNVERIFIED: not tried]`.

   > [!GOTCHA] plasma-apply-colorscheme writes to kdeglobals
   > After the round trip, `~/.config/kdeglobals` had its own `ColorScheme=BreezeDark` line under `[General]` (step 6). A key in that file takes precedence over the `kdedefaults` value, so the scheme was now set in `~/.config/kdeglobals` itself. I put the copy back so the file is as it was. Whether the extra line would block Plasma's automatic switching, I didn't check.
6. **Put `kdeglobals` back.**
   ```console
   $ diff ~/konsole-backup/kdeglobals ~/.config/kdeglobals
   135a136
   > ColorScheme=BreezeDark
   $ cp -p ~/konsole-backup/kdeglobals ~/.config/kdeglobals
   $ diff ~/konsole-backup/kdeglobals ~/.config/kdeglobals
   ```
   Expected: the first `diff` shows what the test added (one line here). After the copy, `diff` prints nothing. The copy brings back the whole file as it was at step 1: if the first `diff` shows more than the `ColorScheme=` line, delete that one line in an editor instead (not tried). Don't remove it with `kwriteconfig6 --delete`: that leaves a `ColorScheme[$d]` marker behind (Failure modes, row 4). I didn't check what copying the file back does to a running session, so finish step 5 on the scheme you want to keep.
7. **Close the test window and restart Konsole.** By its source, Konsole applies the sync when a window is created and when its settings change from inside Konsole (`MainWindow.cpp`), and I didn't check whether a running Konsole notices an outside edit of `konsolerc`. A new Konsole process has it, as the test window did.

## Verify

The file half, in the profile directory and the shell from step 2: two profiles, two different schemes (step 3 already read the keys back).
```console
$ grep -H '^ColorScheme=' "$DARK.profile" "$LIGHT.profile"
user-default.profile:ColorScheme=islands-dark
user-light.profile:ColorScheme=islands-light
```
The screen half, if you saved the screenshots in step 5. Mine were taken at 17:55:57, 17:56:01 and 17:56:05 and are 700×160 pixels; one pixel from an empty part of the background each:
```console
$ cd ~/konsole-test
$ magick 1-dark-start.png 2-after-light.png 3-after-dark.png -format '%f %[pixel:p{5,155}]\n' info:
1-dark-start.png srgb(24,25,27)
2-after-light.png srgb(247,247,247)
3-after-dark.png srgb(24,25,27)
```
Expected: dark, light, dark. The strip below is those three screenshots of the same open window, top to bottom; the ANSI colors change with the background.

![Three screenshots of one open Konsole window, top to bottom: a dark background with a row of colored labels color0 to color7, the same window with a light background and darker label colors after the switch to Breeze Light, and dark again after the switch back to Breeze Dark.](images/konsole-live-switch.png)

## Undo / rollback

In the same shell as step 2 (or set `LIGHT` again first), delete the three keys and move the light profile out:
```console
$ kwriteconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme --delete
$ kwriteconfig6 --file konsolerc --group LightDarkTheme --key LightThemeProfile --delete
$ kwriteconfig6 --file konsolerc --group LightDarkTheme --key DarkThemeProfile --delete
$ mv ~/.local/share/konsole/"$LIGHT.profile" ~/konsole-backup/
$ kreadconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme

$ ls -1 ~/.local/share/konsole/
islands-dark.colorscheme
islands-light.colorscheme
user-default.profile
```
Expected: `SyncProfileWithSystemTheme` is empty again, and the light profile has left the profile directory (it stays in `~/konsole-backup/`). On copies of my files, `konsolerc` came out byte-identical to the pre-change one (`cmp`); the system file `/etc/xdg/konsolerc` sets none of these keys here, so no deletion marker was written. Copying `~/konsole-backup/konsolerc` back gave the same bytes here but also reverts any other `konsolerc` change made since step 1. I haven't rolled back the live desktop. Restart Konsole afterwards, for the reason in step 7. If step 6 was skipped, put `kdeglobals` back as step 6 does.

## Failure modes

| Symptom (exact message) | Cause | Fix |
|---|---|---|
| Plasma goes light, Qt and GTK apps and Kate follow, Konsole stays dark; `kreadconfig6 --file konsolerc --group LightDarkTheme --key SyncProfileWithSystemTheme` prints an empty line | the sync is off, as shipped (`<default>false</default>` in `konsole.kcfg`) | steps 2 and 3 |
| `diff` of the two profiles prints only `7c7`, `< Name=user-default`, `---`, `> Name=user-light` | both profiles use the same scheme: my dark profile had been rewritten with the light scheme during testing. A window in light mode looks right either way (step 5) | copy the dark profile back from `~/konsole-backup/`, run step 2's `diff` again, then steps 4 and 5 |
| after step 5, `diff ~/konsole-backup/kdeglobals ~/.config/kdeglobals` prints `> ColorScheme=BreezeDark` | `plasma-apply-colorscheme` writes the scheme name into `~/.config/kdeglobals` | step 6 |
| after `kwriteconfig6 --file kdeglobals --group General --key ColorScheme --delete`, `diff` prints `> ColorScheme[$d]` and `kreadconfig6 … --key ColorScheme` prints an empty line instead of `BreezeDark` | `kdeglobals` cascades over `~/.config/kdedefaults/kdeglobals`; deleting the key in `~/.config/kdeglobals` writes a deletion marker, which also hides the `kdedefaults` value | copy the step-1 backup back (step 6) |
| delta diffs keep dark backgrounds in a light Konsole | `dark = true` in `~/.gitconfig` turns delta's detection off; the pinned `minus-style`/`plus-style` colors keep dark diff backgrounds, and the dark `syntax-theme` keeps dark highlighting | remove or comment out all of them; I commented them all out together (What follows the switch) |

Row 2 as it looked on my box:
```console
$ cd ~/.local/share/konsole
$ diff user-default.profile user-light.profile
7c7
< Name=user-default
---
> Name=user-light
$ grep ColorScheme user-default.profile user-light.profile
user-default.profile:ColorScheme=islands-light
user-light.profile:ColorScheme=islands-light
```
Row 4, on copies of my files (`~/.config/kdeglobals` as it was after the round trip, and the step-1 backup):
```console
$ kreadconfig6 --file kdeglobals --group General --key ColorScheme
BreezeDark
$ kwriteconfig6 --file kdeglobals --group General --key ColorScheme --delete
$ diff ~/konsole-backup/kdeglobals ~/.config/kdeglobals
135a136
> ColorScheme[$d]
$ kreadconfig6 --file kdeglobals --group General --key ColorScheme

```

## What follows the switch, app by app

Konsole repaints itself, but it can't tell the programs running in it. A terminal program can learn about a theme change while it runs through DEC private mode 2031, and Konsole 26.08.1 doesn't implement it (`Vt102Emulation.cpp` has no handler for 2031 or its 996/997 reports). It does answer OSC 11, the "what is your background color?" query (`SessionController.cpp`), so a program that asks at startup gets the current answer. Versions are the ones installed here.

| App | Follows Plasma | What it takes | Evidence here |
|---|---|---|---|
| Konsole 26.08.1, open windows | live | this manual | observed (step 5) |
| Konsole 26.08.1, new windows | at start | this manual | dark mode observed (step 4); light mode and new tabs from source only |
| Kate and other Qt apps | live | nothing | observed |
| GTK apps | live | nothing | observed |
| delta 0.19.1 | each run | nothing pinned: no `dark` or `light`, no own `minus-style`/`plus-style` colors; for highlighting that switches too, no `syntax-theme` and no `BAT_THEME`, which delta falls back to. `--detect-dark-light` defaults to `auto` | observed: light diff backgrounds in a light Konsole, once the pins were gone |
| bat 0.26.1 | each run | nothing, as long as no `--theme` or `BAT_THEME` pins one: `--theme` defaults to `auto` | docs only |
| nvim 0.11.6 | at start | nothing, as long as your config doesn't set `background`: nvim asks for the background color (OSC 11) at startup; it would also follow live through mode 2031, on a terminal that has it | source |
| Helix 25.07.1 | no | no light/dark theme pair in 25.07.1; master has `[theme] dark`/`light`, picked by mode 2031, so on Konsole it would take its `fallback`, which defaults to the dark theme | docs |
| btop 1.4.7 | not checked | `color_theme = "TTY"` (a built-in theme) and `theme_background = false` (the terminal's background shows through) in `btop.conf` | set here; how it looks not checked |
| JetBrains IDEs | yes, per JetBrains' docs | Settings, Appearance & Behavior, Appearance: "Sync with OS" | docs; here the checkbox was unticked after an IDE upgrade |
| Zed | yes, per Zed's docs | `"theme": { "mode": "system", "light": …, "dark": … }` in `settings.json` | set here; docs |
| Firefox | yes | the "System theme — auto" theme | followed when I looked; once, one toolbar preference still read dark, unexplained (not verified); I found no Mozilla page to cite |

Not checked: Telegram's automatic night mode, Emacs, GIMP, Krita, Blender, darktable, Inkscape.

delta follows only when `~/.gitconfig` leaves it alone. These were the lines in my `[delta]` section that kept it dark; I commented them out:
```text
[delta]
[…]
	syntax-theme = "Visual Studio Dark+"
	dark = true
[…]
	minus-style = syntax "#450a15"
	minus-emph-style = syntax "#600818"
	plus-style = syntax "#0b5858"
	plus-emph-style = syntax "#175959"
[…]
```

## Field notes

- **2026-10-25 18:37, re-run of the file steps — Fedora 44, kf6-kconfig 6.31.0, ImageMagick 7.1.2.34, copies of my files only:** The console blocks in Before you start, steps 1–3, 5 and 6, Verify, Undo and Failure modes row 4 come from one run of exactly these commands, in this order and in one shell, against copies of my files under a scratch home directory, with my session's `XDG_CONFIG_DIRS` order. The copies were the pre-change `konsolerc` and dark profile (the 13:41:59 backups), my two `.colorscheme` files, `~/.config/kdedefaults/kdeglobals` (last written 17:04, before the test) and `~/.config/kdeglobals` as saved just before and just after the 17:55 round trip; the pixel check read the three 17:55–17:56 screenshots. No Konsole window opened and no scheme changed during that run. (The Failure modes row 2 block is older: the live files at 16:44.) Step 2 produced a light profile byte-identical to the one I have used since 13:51:57, step 3 a `konsolerc` byte-identical to my live one, and the undo a `konsolerc` byte-identical to the pre-change backup (`cmp` each). A read of the same key on the live session printed `BreezeDark`, as in step 5.
- **2026-10-25 17:55:57–17:56:05, Fedora 44, Plasma 6.7.5 (plasma-workspace 6.7.5, X11), Konsole 26.08.1, Qt 6.11.2:** The live switch. One `konsole --separate` window, started without `--profile`, while Plasma was dark (Breeze Dark global theme). I copied `kdeglobals` first, then took a screenshot, ran `plasma-apply-colorscheme BreezeLight`, waited 4 s, took a screenshot, ran `plasma-apply-colorscheme BreezeDark`, waited 4 s and took a third. Background pixel 24,25,27, then 247,247,247, then 24,25,27; the ANSI colors changed with it. Those values match my two schemes' backgrounds (25,26,28 and 255,255,255) at their `Opacity=0.97`; the built-in profile's Breeze scheme (35,38,39, opacity 1) would not, so the sync picked my own light and dark profiles. `kdeglobals` came back with one extra line, `ColorScheme=BreezeDark` under `[General]`; I copied the saved file back, and it is identical to the copy now.
- **2026-10-25 17:40, Fedora 44, Plasma 6.7.5 (X11), Konsole 26.08.1:** I put the dark profile back from the 13:41:59 backup (byte-identical afterwards). A new `konsole --separate` window, opened in dark mode, came up dark: background pixel 24,25,27. The dark half had never been tested before this.
- **2026-10-25 16:29, Fedora 44, Plasma 6.7.5 (X11), Konsole 26.08.1:** When I compared the two profiles, they differed only in `Name=`; both pointed at `islands-light` (the block under Failure modes is the re-run at 16:44). The dark profile's file had last been written at 13:49:17, in the middle of that afternoon's light-mode testing. The copy in my dotfiles repository, committed earlier that day, still said `ColorScheme=islands-dark`. Every test until then had run in light mode, where two light profiles look the same as a working pair.
- **2026-10-25 13:41–13:52, Fedora 44, Plasma 6.7.5 (X11), Konsole 26.08.1, delta 0.19.1, btop 1.4.7:** Earlier that day Plasma's automatic switch had turned the desktop light; Qt and GTK apps and Kate followed, Konsole stayed dark. I found the `LightDarkTheme` keys by searching the Konsole library with `strings -e l` (how that went is in the post linked under Notes). I backed up `konsolerc` and the dark profile at 13:41:59 and wrote the three keys right after (`konsolerc` was last written at 13:41:59 and, as of that evening, not since, so my open Konsole windows never rewrote it). The light scheme `islands-light` (13:48:57) came from the light variant of the Zed theme I use: a small converter script turned its `terminal.ansi.*` colors into a `.colorscheme`, and running it again reproduces the file byte for byte. The light profile was written at 13:51:57. My three screenshots of light test windows, at 13:42:24, 13:49:04 and 13:51:03, all predate that file, so none of them tested this setup. delta: I commented out the dark pins in `~/.gitconfig`, and the 13:51:03 window showed a delta diff with light backgrounds. btop: I set `color_theme = "TTY"` and `theme_background = false`, and haven't looked at it since.

## Notes

- The settings-dialog route, read in the v26.08.1 source and not opened here: Konsole's settings dialog, page General, checkbox "Automatically switch profile based on system theme" (widget `kcfg_SyncProfileWithSystemTheme`, bound to the same key). Once that is applied, the Profiles page shows "Set as Light" and "Set as Dark" instead of "Set as Default", and those buttons write `LightThemeProfile` and `DarkThemeProfile`.
- How Konsole decides (source: `MainWindow.cpp`, `ProfileManager.cpp`): it asks Qt for the color scheme (`QStyleHints::colorScheme`). `Dark` gets the dark profile; anything else, unknown included, gets the light one. It sets that profile on every session of the Konsole process when a window is created and again on each `colorSchemeChanged` signal. While the sync is on, `ProfileManager::defaultProfile()`, which new tabs get, returns the light or dark profile instead of the `DefaultProfile=` one.
- The built-in profile, which a misspelled name in step 3 falls back to, uses the `Breeze` scheme, a dark one (source: `Profile.cpp`, `Breeze.colorscheme`; not tried).
- Konsole versions: the setting came with commit e4e20bb6 (merged 2026-04-28). The first stable release with it is 26.08.0; the 26.07.80 and 26.07.90 pre-release tags have it too. Older Konsole has no such setting.
- The keys are compiled into Konsole as UTF-16 strings, so plain `strings` on the library misses them and `strings -e l` finds them. The story of finding the setting is in [Konsole had the switch all along](https://tsvinc.dev/posts/konsole-had-the-switch/).

## Sources

- [Konsole v26.08.1 `src/settings/konsole.kcfg`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/settings/konsole.kcfg) — the `LightDarkTheme` group, its keys and defaults; `UseSingleInstance` default `false`
- [Konsole v26.08.1 `src/MainWindow.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/MainWindow.cpp) — `applyThemeProfile()`, connected to `colorSchemeChanged`, run at window creation and on every settings change
- [Konsole v26.08.1 `src/profile/ProfileManager.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/profile/ProfileManager.cpp) — light/dark profiles looked up by name with built-in fallback; `defaultProfile()` following the scheme
- [Konsole v26.08.1 `src/profile/Profile.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/profile/Profile.cpp) — default `ColorScheme` of the built-in profile, `Breeze`; [`data/color-schemes/Breeze.colorscheme`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/data/color-schemes/Breeze.colorscheme) — its dark background
- [Konsole v26.08.1 `src/colorscheme/ColorSchemeManager.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/colorscheme/ColorSchemeManager.cpp) — where a scheme name is looked up; [`data/data.qrc`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/data/data.qrc) — the bundled schemes
- [Konsole v26.08.1 `src/main.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/main.cpp) — `--separate` always starts a new process
- [Konsole v26.08.1 `src/settings/GeneralSettings.ui`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/settings/GeneralSettings.ui) — the checkbox; [`ProfileSettings.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/settings/ProfileSettings.cpp) — the Set as Light / Set as Dark buttons
- [Konsole commit e4e20bb6](https://invent.kde.org/utilities/konsole/-/commit/e4e20bb6e65dd175240796eb533760d4239b7a63) — "Add automatic profile switching based on system theme", merged 2026-04-28
- [Konsole v26.08.1 `src/Vt102Emulation.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/Vt102Emulation.cpp) — no handling for mode 2031 or the 996/997 reports; [`src/session/SessionController.cpp`](https://invent.kde.org/utilities/konsole/-/raw/v26.08.1/src/session/SessionController.cpp) — `sendBackgroundColor`, the OSC 11 reply
- [plasma-workspace v6.7.5 `kcms/colors/plasma-apply-colorscheme.cpp`](https://invent.kde.org/plasma/plasma-workspace/-/raw/v6.7.5/kcms/colors/plasma-apply-colorscheme.cpp) — the "already set" check and the success message
- [Contour: Dark and Light Mode detection](https://raw.githubusercontent.com/contour-terminal/contour/master/docs/vt-extensions/color-palette-update-notifications.md) — the mode 2031 spec
- [Neovim `_defaults.lua` at v0.11.6](https://raw.githubusercontent.com/neovim/neovim/v0.11.6/runtime/lua/vim/_defaults.lua) — the OSC 11 query at startup; [commit d460928](https://github.com/neovim/neovim/commit/d460928263d0ff53283f301dfcb85f5b6e17d2ac) — mode 2031 support, first released in 0.11.0
- [Helix master `themes.md`](https://raw.githubusercontent.com/helix-editor/helix/master/book/src/themes.md) — `[theme] dark/light/fallback`; [PR #14356](https://github.com/helix-editor/helix/pull/14356) — merged after 25.07.1
- [delta 0.19.1 `--help`](https://raw.githubusercontent.com/dandavison/delta/0.19.1/manual/src/full---help-output.md) — `--detect-dark-light`, default `auto`; [`src/options/theme.rs`](https://raw.githubusercontent.com/dandavison/delta/0.19.1/src/options/theme.rs) — `--dark`/`--light` skip detection, a pinned syntax theme doesn't; the syntax theme falls back to `BAT_THEME`
- [bat v0.26.1 CHANGELOG](https://raw.githubusercontent.com/sharkdp/bat/v0.26.1/CHANGELOG.md) — automatic theme from the terminal's colors, since v0.25.0
- [btop v1.4.7 `src/btop_config.cpp`](https://raw.githubusercontent.com/aristocratos/btop/v1.4.7/src/btop_config.cpp) — the `TTY` theme and `theme_background`
- [JetBrains: Appearance settings](https://www.jetbrains.com/help/idea/settings-appearance.html) — "Sync with OS"
- [Zed: Appearance](https://zed.dev/docs/appearance) — `"mode": "system"`