For example, PS1 of this CentralAuth patch: https://gerrit.wikimedia.org/r/c/mediawiki/extensions/CentralAuth/+/982144/ is showing PCC under "error" in the checks tab:
E.g.
- https://gerrit.wikimedia.org/r/c/mediawiki/core/+/982170
- https://gerrit.wikimedia.org/r/c/mediawiki/extensions/TimedMediaHandler/+/982435
It seems any patch with a check experimental trigger, is attempting to render a link to a Puppet Compiler result.

