It’s something like win-ctrl-f23

(Despite the physical buttons having been missing for a long time on regular keyboards, there are still scancodes for f13-f24)

For what it’s worth too, the Windows “Powertoys” utilities have always been able to remap it.

by the small icon it must be opening the context menu at the currently focused place.

standard, surprisingly enough, it’s essentially just a shortcut to the key combination ctrl+shift+f23. guess microsoft figured they couldn’t leave all the extra F keys unattended

Probably Ctrl + shift + win + alt + C, or something like that. The same modifiers + first letter of the program work for other services like word and linkedin