I quote from my original bug report:
Currently, help-follow and help-follow-mouse signal an error if there's
nothing to follow. However, help-follow-symbol does not, which means
that C-c C-c in the help buffer when over an arbitrary non-symbol does
nothing and says nothing.
That's not just inconsistent, but a bit disconcerting, as sometimes
following a symbol can be slow. In my build, it takes a second or more
to show the symbol documentation, so when there's no symbol I stand
waiting for something to happen for a couple of seconds.
Ok.