The page meta:MediaWiki:Centralnotice-template-stewnoms and many many others like that are really ugly:
- They do not have syntax highlight
- They do not have CodeEditor
- They will not be subjected to syntax validation (T76204) and are loaded in many wikis
- They would probably be ignored by the new 'editsitejs' and 'editsitecss' user rights proposed in T72182
- They do not show up in mw-grep results used to update deprecated code (things like T86871 and T123314)
- Do they have proper caching?
- Are they ResourceLoader modules?