PSGML broken?

[Ulrich Deiters]

Greetings!

I have recently upgraded to Emacs 27.2 (under openSUSE Leap 15.4) and
find that the "markup menus" (which let me select XML/SGML tags as well
as tag options depending on the context.

PSGML is installed on my computer, but I do not see it in the list
of installable packages any longer.

Shift-F10 merely invokes the drop-down menus from the menu bar (e.g.,
the "File" menu).

The Emacs Wiki on PSGML (https://www.emacswiki.org/emacs/PsgmlMode)
mentions the Marmalade repository as well as the main PSGML page;
both links are dead.

Does someone know how to restore the previous behavior?