This are the FrameTypes used in the fdfAction Frame, they uppercase only and a expected to be inside "".
Frames can be seen as seperated into 2 Groups: Frames and SimpleFrames. While both can use most Frame-natives, they work quite different from each other and can not be parent/child for the other group.
SimpleFrames are: SIMPLEBUTTON, SIMPLECHECKBOX, SIMPLEFRAME, SIMPLEGRID, SIMPLESTATUSBAR and the special Child-Frames String and Texture.