This file seems to be rather old and a lot of it's content is local and not accessible from the outside.
In order to modify some things like the style of a unit frame, it would be nice if we could access variables and functions that are used to define them.
EDIT: Some examples:
- KEYBOARD_CONSTANTS
- GAMEPAD_CONSTANTS
- groupFrameAnchor
- UNITFRAME_BAR_STYLES
- GetPlatformBarStyle
- IsValidBarStyle
- CreateBarStatusControl
- CreateBarTextControls
- UnitFrameBar
- GetVisibility
- UNITFRAME_LAYOUT_DATA
and many more