If I recall correctly: with the classic look, URLs for add-ons – including abbreviations such as the one above,
https://addons.mozilla.org/addon/febe/ – resulted in embedded previews in Mozilla Discourse.
An alternative test, although I doubt that this instance of Discourse is (or should be) prepared to embed content from this domain:
Third test, development domain, without the abbreviation:
Fourth and final, production, without the abbreviation:
@jorgev just FYI – I don’t imagine that there’s anything for you folks to do on the AMO side.