NazoFinally got around to dealing with getting rid of that geoclue crap as an autostart on my system. (Literally the stupidest possible reason to use something that identifies a user's location and could potentially be used for tracking is... so that it can try to guess sunup/sundown times for screen filters rather than just using the clock or user manual control...)
The simplest way for a lot of this stuff is to copy the autostart entry from /etc/xdg/autostarts/ to ~/.config/autostarts/ and edit it to say "Hidden=true" for KDE and I think X-GNOME-Autostart-enabled=false for GNOME, but I found a great thread for more troublesome services as well as tracking down some of these things: https://discuss.kde.org/t/ssh-hack-block-kde-ssh-agent-autostart/18201/8 (systemd-cgls is super useful!)
Good riddance geoclue.
SSH Hack - Block KDE ssh-agent Autostart
It is useful to understand what the terms mean: a “slice” is just a namespace for controlling resource allocation to a group of processes (see man:/systemd.slice for more details) and it doesn’t start stuff by itself - when stuff starts, it gets put into a slice. System services get put into the system.slice while user stuff gets put into the user.slice that is then sub-sliced into a slice per user, in it there’s the app.slice, the background.slice, the session.slice, and probably a few others. ...