nil has a plist, of course.

[Aidan Kehoe]

And on two non-vanilla invocations of mine it’s non-nil. These seem like
bugs:

(object-plist nil)
=> (custom-group ((vm-coding-system-priorities custom-variable) (vm-mime-ucs-list custom-variable) (view-mode-line-string custom-variable)))

(object-plist nil)
=> (custom-group ((view-mode-line-string custom-variable)))


-- 
Santa Maradona, priez pour moi!