>>>> Like e.g. 'quit-window' allows using a prefix argument
>>>> to change its behavior by relying on (interactive "P"),
>>>> xref-goto-xref should do the same:
>>>
>>> The proposed change is not quite the same (bury instead of kill), but if it
>>> really helps, go ahead.
>> I don't know how important would be to kill *xref* instead of burying.
>
> Indeed, probably not at all important. I'm just saying the parallel seems
> very rough.
>
> Which might or might not be important from the standpoint of trying to
> unify different behaviors in Emacs, to make them more "regular".

What do you think about adding a prefix arg 'KILL' to xref-pop-marker-stack
that would behave exactly like the same arg 'KILL' in quit-window?

This is very useful when there is a need to quickly peek with 'M-.',
and to kill the temporary buffer when going back with 'C-u M-,'.

Here is the implementation: