robot-mode.el wishes it was a package

[bhyde]

and it appears somebody else already did the markup.

So, this worked around the problem:

(use-package robot-mode
  :mode "\\.robot\\'"
  :quelpa (robot-mode
           ;; :url "https://raw.githubusercontent.com/sakari/robot-mode/master/robot-mode.el" ;; sad, it's not a "package"
           :url "https://raw.githubusercontent.com/paulohefagundes/.emacs.d/0cb9f8d2b6ad6d0ac675be315a528ab090dbd2e2/vendor/robot-mode.el"
           :fetcher url))