Here you go:

(transient-define-prefix demo ()
  [(:info "boring" :face shadow)
   (:info (lambda () (format "Major-mode: %s" major-mode)))
   ("x" transient-echo-arguments)])
(keymap-global-set "" #'demo)

You are welcome!

This changed with https://github.com/git/git/commit/92156291ca82ae4f4ad09fde8181c5f2b7dba6ca.

You can revert to the old ways with git config --global log.initialDecorationSet all. I'll have to think about how to best deal with that in Magit.

Exactly.

When you add the current repository to the forge database, then that also takes care of adding the appropriate fetch refspecs.

When you remove and then clone again a git repository, which was already being tracked in the forge database, then you don't have to add the repository to the forge database again. But that means that the step where the fetch refspecs are added, also won't be run again.

But you can use M-x forge-add-pullreq-refspec to add them explicitly. Also see the option by the same name.