Michael Tsai listed everything that’ll be disappearing with the release of macOS 10.14 Mojave (that we know of) and there are a few surprises in there. Firstly, I’m disappointed that subpixel antialiasing will not be around anymore, since a lot of people still don’t use Retina screens (especially when using external displays connected to their Macs). I’m also quite concerned about Safari Extensions getting deprecated, especially in regard to content blockers — I wonder if they have some soft of replacement planned. Oh — unsigned Safari Extensions are already completely axed.
Update on Safari Extensions
Support for .safariextz-style Safari Extensions installed from the Safari Extensions Gallery is deprecated with Safari 12 on macOS. Submissions to the Safari Extensions Gallery will no longer be accepted after December 2018. Developers are encouraged to transition to Safari App Extensions.