Lisp help messages in echo area

[john@ankarstrom.se (John Ankarström)]

Hello all,

I have a really simple question: what function triggers the Emacs
Lisp help messages in the echo area?

For example, when I put my cursor inside a (defun) expression,
the following displays in the echo area:

--8<---------------cut here---------------start------------->8---
defun: (NAME ARGLIST &optional DOCSTRING DECL &rest BODY)
--8<---------------cut here---------------end--------------->8---

This appears to trigger when moving the cursor, but also when
inserting a character. These are two good clues, but I haven't
been able to find it. I haven't yet looked in the Emacs C source
code -- I send this e-mail message hoping that somebody knows the
answer, before I have to get into the C source.

I'm asking because I'd like to fix the function
`outshine-self-insert-command' from the `outshine' package, which
doesn't trigger the Lisp help message, unlike the default
`self-insert-command'.

If anybody knows the answer, or has any pointers as to where I
should look, I'd be greatful.

Thanks,

- John