This allows the style to work with tabs_on_bottom.css without causing
tabs to appear when close to the top of the web-content, which would
make top ~36px inaccessible.
In the Tor browser user agent, the "geckotrail" part has been changed.
Apparently following an upstream change in Firefox:
> From Firefox 10 on mobile, geckotrail is the same as firefoxversion.
Note: I'm simply running latest Tor browser on Android and visit
websites showing the user agent to figure out the latest one. I tried to
figure it out from the source code once, but didn't find a place where
it could be looked up trivially (since it gets built of multiple
components etc.).
Related: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent/Firefox
For some distros (including Debian), the Firefox config directory can be
different from `/etc/firefox`. Adding a variable for this location so it can
be easily customized at build time.
Preferences set with `pref()` can be changed by the user, but they're
then reset on each Firefox startup.
As users may want a different UA and keep it persistent, we should set
the default value with `defaultPref()` instead. This requires moving the
preference to the autoconfig file though, as `defaultPref()` isn't
recognized in the main config file.
To allow downloading the package directly from GitLab and not having to
run make install (e.g. to easily try a specific MR); also makes it
easier to check in a MR if make install works as expected.
Variable values are defined such that Firefox' own rules will override
them where applicable (Win10 currently). This change lets us simplify
css by not requiring fallback values and it is clearer since color definitions are all in one place.
that should have already been the case previously, but if one were to
use some other custom style that added .tab-background::before pseudo
element, then all tabs would have a playing animation which would have
trashed performance.
