While looking for raw html messages (for T200997), I came up with a grep:
for i in `find . -name '*.js' -type f` do if tr $'\n'$'\t' ' ' < "$i" | grep -o -e '[^ ]*\.html(\s*\(mw\.msg\s*([^()]*\([^()]*([^()]*)[^()]*\)*)*\|mw\.[mM]essage\s*([^()]*\([^()]*([^()]*)[^()]*\)*)\s*\.\s*\(params(\([^()]*([^()]*)[^()]*\)*)\.\)*\(plain\|text\)\s*(\s*)\)\s*)*' then echo $'\t'--^ Raw html message in file "$i";fi; done
While this will obviously miss a lot, it seems to have an extremely low false positive rate. Maybe it is worth adding to CI as a quick and dirty check.