I wanted to make a software with Godot in GDScript that advice you when pressing the bloq mayus button changing the color of the taskbar icon. But, I couldn't find any special code or something that makes it.
I saw the video of Adderly Cespedes making the same software (but in gamemaker) and he said that he found a special extension for it but never said the name.
This isn't currently possible in Godot.
The engine doesn't allow you to map Caps Lock (bloq mayus) to an input.
Edit: From Calinou’s comment, OS.request_attention()
can be used to flash the taskbar.