Firefox-based browser support

[Guuri11]

Firefox-based browser support

Browsers like Zen Browser, Firefox, LibreWolf, Floorp, etc. don't support the
--app flag (Chromium-only). As a result, web apps fail silently or open the
browser without navigating to the URL.

Proposed fix

Detect Firefox-based browsers and use --new-window instead of --app:

case $browser in
google-chrome* | brave* | microsoft-edge* | opera* | vivaldi* | helium*) browser_type="chromium" ;;
zen* | firefox* | librewolf* | floorp* | waterfox* | mercury*) browser_type="firefox" ;;
*) browser="chromium.desktop" ; browser_type="chromium" ;;
esac

browser_bin=$(sed -n 's/^Exec=\([^ ]*\).*/\1/p' {~/.local,~/.nix-profile,/usr}/share/applications/$browser 2>/dev/null | head -1)

case $browser_type in
firefox) exec setsid uwsm-app -- "$browser_bin" --new-window "$1" "${@:2}" ;;
*)       exec setsid uwsm-app -- "$browser_bin" --app="$1" "${@:2}" ;;
esac

Note: Firefox doesn't support true app-mode (no browser chrome), so --new-window
is the closest equivalent available.

[LurkAndLoiter]

Might be worth looking into Mozilla's -kiosk flag. There are some hurdles like opening into fullscreen but the window does play nice with hyprland after that.

[Auxxed]

+1 on launching webapps through Firefox-family browsers instead of silently falling back to Chromium.

This is not just a preference on my machine. Omarchy already lets me set Firefox as the default (omarchy default browser → firefox), and normal browsing is fine. Webapps still ignore that: omarchy-launch-webapp (and the Super+Shift bindings) whitelist Chromium-family browsers and hard-fall back to chromium.desktop so they can pass --app=. That forces Chromium onto NVIDIA hardware where Chromium's media path is currently crashing.

NVIDIA + Chromium on this box

Same class of failure as #6024 (Chromium/Brave SIGILL in the renderer Media thread on NVIDIA; NVIDIA bug 5762513, BAR1 mapping of video frames).

Omarchy	4.0.2-1
GPU	NVIDIA GeForce RTX 3080 LHR (GA102)
Driver	nvidia-open-dkms 610.57.04-1
BAR1	256 MiB total (no Resizable BAR), ~161 MiB used
Chromium	151.0.7922.173-1
Firefox	154.0-1 (already the XDG default)
Session	LIBVA_DRIVER_NAME=nvidia NVD_BACKEND=direct

Four SIGILL (ILL_ILLOPN) dumps of /usr/lib/chromium/chromium in two days, all in a renderer --type=renderer Media thread:

• 2026-09-02 16:20 PID 8472
• 2026-09-02 17:27 PID 70690
• 2026-09-03 19:07 PID 112766 (webapp: chromium --app=https://omarchy.org/manual/)
• 2026-09-03 19:21 PID 117777 (webapp: chromium --app=https://x.com/)

--disable-gpu-video-decode is already in ~/.config/chromium-flags.conf as a workaround for that NVIDIA BAR1 OOM → Media SIGILL. It is not enough; the Media thread still dies. So every Omarchy webapp keybind is a Chromium launch I would rather not take.

Firefox has no Chromium --app mode

Verified on Firefox 154 here. --app is XUL application.ini, not a site-specific browser. --new-window <url> and --kiosk are the nearby flags. That matches the finding on #7039 — allowlisting Firefox and still passing --app=<url> will not produce an app window.

What I'd like

1. Honor a Firefox-family default with --new-window <url> (this discussion's proposal). Not chrome-less, but it stops forcing a browser that SIGILLs on this GPU.
2. Even better: a separate "webapp browser" default, so Firefox can stay the tab browser while --app windows remain optional Chromium-family — or are skipped entirely when Chromium is unstable.
3. Please don't treat "default is Firefox" as "pretend Chromium is installed" (launch webapp fails when default browser is Firefox (no Chromium installed) #7034 / Fall back to an installed Chromium-family browser in omarchy-launch-webapp #9172). When the user picked Firefox, use it.

Happy to test a --new-window fallback on this NVIDIA box.

Filed by Grok 4.6 via Grok Build.