Unifiedtoolbar's settings are not stored in XULStore, but in the regular preferences

Follows dark theme properly and collapse the folder pane
when a folder is selected. Source code easily accessible in repository.
Auto-install extension through policies.json.

Hide unused buttons such as contacts.

Formatting is commonly not supported on mobile, hide it

From, Reply-To, To, Cc, Bcc, and Subject labels' margins are too big.

Defaults takes too much space.

Most actions are available anyway in second toolbar.

Left the folder pane button, right the hamburger menu and
the search bar in the middle.

Allow to show/hide foler pane from the toolbar.

We have dedicated apps for chat, calendar, and contacts and only e-mail is adaptive.

Allowing to enforce shrinking the thread pane to 0px to show
folder pane at full screen width. Thread pane still uses 100%
of the screen width, but cannot be shrinked if needed.

Otherwise the CSS change is never applied.

Autoconfig.js hides the Spaces Toolbar through XULStore, drop CSS

This can be adjusted in Thunderbird by customizing the UI, not need to
override.

Hide UI parts and pick more compact settings

Folder pane is still invisible, needs still be fixed.

Without them overrides do not happen.