Since the5e1470d1b3/0f51b5b599the `fmodifier_add` operator has moved to the Channel menu in the Graph Editor and also the channels context menu in the channels region. The shortcut was not working in the channels region though since the operator was only in the keymap for the main region (not the channels region). Now move the keymap entry to the generic keymap of the Graph Editor so it works in both regions. Pull Request: https://projects.blender.org/blender/blender/pulls/111378