keymaps

[User Elisej]

I need to understand and write keymaps.
I have read kbdcontrol(1) and kbdmap(5), but these two is too superficial.
Is there another document?

These manuals do not explain for example:
How to make "Alt+a" acting as sequence "Meta a"?
"Alt+a" acts in other way, than "a" pressed after the key marked as "alock" in keymap. So what is alock?
When a locked key is unlocked?
Should I describe scan codes 128-255? (Some standard keymaps do this, but some standard keymaps do not.)
How kbdmap affects on LEDs?
and so one and so forth.

I have asked this question in freebsd-questions already. No response. So, I decided to ask here.

Elisej Babenko
mailto:a at zeos.net