https://gist.github.com/XVilka/8346728#true-color-detection
OSC
- OSC 0 - change window icon + title (but only title is actually supported)
- OSC 2 - change window title
- OSC 4 - change color palette
- OSC 7 - report CWD
- OSC 8 - hyperlink
- OSC 9 - desktop notification
- OSC 10 - change (default) foreground color
- OSC 11 - change (default) background color
- OSC 12 - change cursor color
- OSC 17 - change highlight (selection) background color
- OSC 19 - change highlight (selection) foreground color
- OSC 52 - copy/paste clipboard data
- OSC 104 - reset color palette
- OSC 110 - reset default foreground color
- OSC 111 - reset default background color
- OSC 112 - reset cursor color
- OSC 117 - reset highlight background color
- OSC 119 - reset highlight foreground color
- OSC 555 - flash screen (foot specific)
- OSC 777 - desktop notification (only the ;notify sub-command of OSC 777 is supported.)