v0.13.0 — a real install, and previews that notice new views

Three changes, one of them the feature install was always pretending to be.

fxcss install — a real install, with a way back

Until now install was an alias for try: a themed throwaway profile that vanished on exit. It now installs into your actual profile — the one Firefox itself opens, found via profiles.ini — and can undo itself:

fxcss install AdamXweb/WhiteSurFirefoxThemeMacOS
fxcss install owner/theme --with compact-tabs,noidentity   # optional sheets too
fxcss uninstall

Your existing chrome/ is backed up first and a manifest records every file written, so uninstall removes exactly what was installed and restores the backup. Files fxcss did not write are never deleted — the manifest is treated as untrusted on the way back out, so a doctored one cannot reach outside chrome/. --with lands optional sheets where the theme's own @imports expect them, --profile picks a non-default profile, --list-profiles shows what was found.

Preview comments notice brand-new views

A PR that adds a variant stylesheet used to read "no visual change" — its captures exist only on the head side, so there was nothing to diff. compare now lists them in summary.only_in_head, and the publish workflow renders each one as "new in this PR". The PR whose whole point is a new look finally looks like one.

Windows runners: startup race fixed

Intermittently on windows-latest, the first loadURI of a session died with TypeError: … this._browser.frameLoader.remoteTab is null — Marionette answers commands before the initial browser has attached its content-process handle. setup_window now polls that exact attachment point (best-effort, 10s) and retries the tab setup only for this specific race; every other error surfaces unchanged. Found twice in WhiteSur preview CI, at 0.9.0 and 0.12.0.

One subtlety the fix itself uncovered: the initial browser can be a lazy browser whose frameLoader does not exist until a load forces it into existence — so the poll treats "no frameLoader" as ready rather than deadlocking on it, which the first CI run of the fix demonstrated in practice.

Verified on 153.0.4: full smoke runs green on macOS, Windows and Linux, and the unit suite grows from 49 to 84 — the install/uninstall filesystem paths, the head-only summary handling, and the startup-race error classifier are all pinned without needing a Firefox.

pipx upgrade fxcss