Add README to Tor Browser
I am struck that there is none.
tor-browser8.5a1$ find |grep -i readme
./Browser/TorBrowser/Docs/Obfsproxy/README
./Browser/TorBrowser/Docs/fteproxy/README.md
./Browser/TorBrowser/Docs/meek/README
./Browser/TorBrowser/Docs/libfte/README.md
./Browser/TorBrowser/Docs/snowflake/README.md