As of Windows 10.0.27729.1000
AltGr: The layout treats right Alt key as Control+Alt.
ShiftLock: The layout turns off Caps Lock when Shift is depressed.
Directionality: The layout inserts Left-to-Right Marker (LRM) on Left Shift+Backspace and Right-to-Left Marker (RLM) on Right Shift+Backspace. Furthermore, Left Shift+Ctrl and Right Shift+Ctrl change the directionality of a paragraph, or a text box to LTR and RTL respectively.
KLLF_ALTGR = 1
KLLF_SHIFTLOCK = 2
KLLF_LRM_RLM = 4