There are many packages with non-dot author/maintainer format that fail with

Debugger entered--Lisp error: (wrong-type-argument listp "XXIV")
  car("XXIV")
  package--print-email-button("XXIV")
  describe-package-1(#s(package-desc :name chaos-mode ((:authors ("XXIV")) (:maintainers ("XXIV")) (:maintainer "XXIV"))))
  describe-package(#s(package-desc :name chaos-mode ((:authors ("XXIV")) (:maintainers ("XXIV")) (:maintainer "XXIV"))))
  package-menu-describe-package(#<marker (moves after insertion) at 67389 in *Packages*>)
  button-activate(#<marker (moves after insertion) at 67389 in *Packages*> nil)
  push-button(67389)
  funcall-interactively(push-button 67389)
  command-execute(push-button)

Here is the fix: