Are there established way(s) on Linux to have windows maximize to a particular area of an ultra wide screen instead of filling it?
It can be done in TWMs but I haven’t heard of anything for regular DEs like XFCE, MATE, ect.
fyi… I don’t own an ultrawide but I stretch remote viewers across 3 screens so I get the same problems of an ultrawide. I could mess with multiple viewers connecting to dummy monitors on the remote but it’s a mess and i’d really prefer and ultrawide solution. In my dreams i’ll have this problem natively. 
Progress:
Idea: I could map a particular key combo to a wmctrl bash script. It’d read the position of the focused window, then use a user generated config to find out which “zone” it’s in and resize it to fill that zone.
No go: xdotool allows you to map events to commands but it only works with mouseover and focus, not movement.
Working on: Ways this can be done natively so it’ll work with regular maximize.