Re: undo in loaddefs.el buffer

[Richard Stallman]

    All known examples write into buffers that are current

No, most timers do not.  I found about 40 places in Emacs that create
timers, and these are just two of them.

There is no need for the manual to explain all the ways of writing
code that could possibly be made to work.  That is not the manual's job.
However, I found a simple way to improve the text.

It is normal that there is code in Emacs that does things the manual
says users shouldn't do.  Writing the manual in such a way that no code
in Emacs ever goes against its recommendations is not the goal.
       And they have to take special measures to deal with the consequences
       of violating the rule.

    Some of which are obvious and some of which are non-obvious.  My
    proposal is to point out the latter.

Could you please explain these special requirements in the comments in
autorevert.el, if that isn't already done.