The regex expected JSON — "appSubUrl":"…" — and Gitea emits a JavaScript object
literal: unquoted key, single quotes, `appSubUrl: ''`. So the single
highest-value rewrite in this file silently did nothing on every real page,
while every attribute around it rewrote perfectly.
The test used the shape I guessed rather than the shape Gitea produces, which
is why it passed. Now covers both, with the real form taken verbatim from a
live response, and asserts the quote style survives — swapping it would stop
the literal parsing.