I am going to close this.

Nosy lists are documented in the user guide: https://www.roundup-
tracker.org/docs/user_guide.html#nosy-list

Superseder is a generic issue to issue linkage. It has no logic
behind it to enforce any sort of relationship.

I added info on the "Make a copy" link to the user guide.

Popups are problematic. On a tablet there is no way to trigger
it since there is no hover. Making the label a link is frowned upon 
because screen readers have issues with them and clicking on the label 
will not focus on the input field, it will trigger the link instead.
A help link icon could work I guess.

Patches thoughtfully considered.

-- rouilj