Deleting a tag whole is what lets a filter like this be reassembled around: strip the `<b>` out of `<scr<b>ipt>`
and the two halves close up into a tag nobody wrote. The leftovers are escaped one character at a time instead,
which also covers `-->` in cue text without a second multi-character replacement.
Both are what CodeQL flagged on the branch, js/incomplete-multi-character-sanitization and js/bad-tag-filter.
Neither was reachable as an injection, because the file is served as text/vtt and a cue is parsed by the WebVTT
cue-text parser rather than as HTML, but a sanitiser that cannot be reassembled around is the cheaper thing to own.
yusufipek
a709ca8544