This URL is 404: https://www.torproject.org/PT It only works if you remember to type a slash at the end: https://www.torproject.org/PT/ (redirects to https://www.torproject.org/docs/pluggable-transports) I wanted to write down a short URL representing pluggable transports, and it was awkward to explain to people that the slash at the end is necessary. The URL without a slash appears in the PT animation: https://blog.torproject.org/blog/breaking-through-censorship-barriers-even-when-tor-blocked The existing redirect was added in legacy/trac#19547. The `^PT/$` pattern is mentioned in comment:8:ticket:19547.