We're setting `MOZ_REQUIRE_SIGNING=0` during build, so it's possible to
set `xpinstall.signatures.required` to `false` in `about:config`, should
it be desired to install unsigned addons, while still keeping signatures
required by default with this change.
This is basically backporting some changes that have been already
implemented with my earlier Arch builds.
Mostly it's about keeping some of the settings most often causing
"issues" unlocked, to make it easier to change them once needed.
Cookie handling, for example, can be handled via
[Cookie AutoDelete](https://addons.mozilla.org/de/firefox/addon/cookie-autodelete/)
more comfortably, allowing exceptions for websites and a more granular
retention / rejection.
Having the option to actually keep a history or autofill forms can also
be desired, when the tradeoff with regards to privacy implications is
understood and accepted, so while keeping those options off by default,
it might be helpful to have them easily modifiable.
`resistFingerprinting` can cause issues (rarely), so it might be desired
to at least temporarily disable it in some cases.
The predefined useragent and other overrides sometimes cause issues with
certain websites, so being able to modify can be required as well.
The webextensions-CSP needs to be slightly modified to allow some addons
(especially μBlock Origin) to function.
Furthermore, options to allow re-enabling installing (and, optionally,
updating) extensions from the official extension store might be a good
thing, albeit somewhat of a tradeoff between privacy and security:
Basically keeping extensions up to date is crucial from a security point
of view, and the official extension store is at least a somewhat trusted
source of extensions. This also indirectly can be a good thing for
privacy, as in keeping relevant addons current with regards to privacy
enhancing techniques.
Of course, extensions can be kept up to date separately as well, but
from my experience this is often not taken care of properly and quite a
lot of extra work.
In a comparable vein, the `xpinstall.signatures.required` option might
be a good thing, but also undesired – so it's just kept unlocked.
