First, let me share Mozilla’s release note for 59.0
I’ve checked with Arch’s PKGBUILD
And the following line is the most important one to a regular user IMHO.
Here is what you should know,
- the property
general.useragent.localeno longer applied, it is safe to reset it, and it would disappear the next start.
- instead, the
intl.locale.requestedproperty takes into place. This property should remain NULL, and would be override by the locale package installed.
- the CSD patch is merged upstream, however, it is disabled by default on KDE environment. You can check for the window control addons, customize them in place and disable window title and decoration in kwin setting manually.