List of allowed keyboard keys in "flirc record" is incomplete

[KlausMu]

Here you can see which keyboard keys are reported that can be used in flirc_util record <keboard key>:
prev_track

"valid commands:"
"  a-z <any single letter>"
"  return, enter, escape, backspace, delete, tab, "
"  space, F[1-12], print_screen, scroll, pause, insert, "
"  home, pageup, pagedown, end, right, left, down, up, "
"Media Keys: "
"  wake, eject, vol_up, vol_down, mute, play/pause, stop "
"  rewind, fast_forward, next_track, prev_track "
"System Keys: "
"  suspend"
"Other: "
"  toggle [enables/disables] flirc",

But in fact, there are more keys that can be used, e.g. "browser_back" and "browser_home". They can also be seen in the binary file "libflirc.dll" and can be set with the GUI.

Could you please provide a complete list of all supported keyboarde keys?

I am especially interested in the key "menu" from the FireTV remote.

If an IR code is recorded with the GUI, I can see a setting like this:

Recorded Keys:
Index  hash       IK   ID  key
-----  --------   ---  --  ------------
   12  16AFBFB2   043  01  ! 

But if I use "flirc_util record !", it gets recorded as

Recorded Keys:
Index  hash       IK   ID  key
-----  --------   ---  --  ------------
   12  16AFBFB2   043  01  left_shift!   

and does not work.

How can I record this key with CLI?