OG image text no longer unescapes twice. Entities were decoded in sequence with & first, so a title containing the escaped text &lt; came out as <. Decoding is now a single pass, and escaped text stays escaped.
The meta-refresh patterns used to rewrite legacy .html redirect pages are bounded. The previous patterns scanned the rest of the page from every start position, so time grew with the square of the page size: a 200 KB page of near-matches took over half a second. A tag longer than the bound is left alone, which skips hash forwarding for that page but keeps the redirect.