"cut here" (and message formatting in general)

[Tamas K Papp]

Hi,

Reading a newsgroup recently in Gnus I found a message which had code
nicely highlighted in the Emacs buffer.  Looking at the raw message
source I found something like

--8<---------------cut here---------

around the code.

I was not aware of this possibility, so now I am interested in the
following:

1. What's the "standard" format for this, or at least the format
recognized by Gnus?

2. Is there an emacs function or some other shortcut to enter it?

3. Is there a list of similar constructs that Gnus would recognize (I am
aware of *bold*, _underline_ and /italic/, but I am interested in what I
am missing).  If there is no user-friendly list I am happy to look at EL
sources, but some directions would be useful.

Best,

Tamas