is there a way? (or what is the shortest way)
You could copy them onto a cube, and then copy that cube between files… Not sure if that’s best though.
keys form bones to another windows’ bones i mean…
I learned another way. Open blender (just one blender window). Select and copy the keys of the character’s bones’. And close the scene (dont close blender). Open the other scene, (maybe another) character and paste the keys to the bones (bones names must be the same). That’s it.