I just wrote about this on
gmane.emacs.help/gmane.emacs.erc.general so I'll just reuse
that, I think it is clear what I mean :) Keep it up...

2. What is `this-convention' and ‘this‘? I always used
   `this-one' - I don't know/remember why, probably I saw
   someone else do it - but it seems in the on-line (*) help
   ‘this‘ is what happens, indeed even if you use
   `the-other-one' [see this example [1]]

3. In ERC, for example `sentence-end-double-space' gets turned
   into a button that opens up a help buffer, however with the
   other convention, i.e. ‘sentence-end-without-period’,
   nothing happens. maybe ‘this’ doesn't get
   highlighted/buttonized/hyperlinked because people use it
   for other things than to denote Emacs references?
   Emacs references? naah! Anyway here [2] is a screenshot [2]
   which is also attached to this post that shows what
   happens/how it looks.

(*) On-line help means it isn't on paper :)

[1] https://dataswamp.org/~incal/emacs-init/wrap-search.el
[2]
https://dataswamp.org/~incal/figures/emacs/erc-docu-button-again.png