Function: describe-text-properties

Describe widgets, buttons, overlays, and text properties at POS.
POS is taken to be in BUFFER or in current buffer if nil.
Interactively, describe them for the character after point.
If optional second argument OUTPUT-BUFFER is non-nil,
insert the output into that buffer, and don't initialize or clear it
otherwise.

(fn POS &optional OUTPUT-BUFFER BUFFER)