Can you really not draw a distinction between appspot and google.com? They run googleusercontent.com to maintain that separation for Google Cache, after all.
There's a pretty good write up I found here:
https://trac.torproject.org/projects/tor/wiki/doc/meek
commit for the ios version is here:
https://github.com/WhisperSystems/SignalServiceKit/commit/78...
signal-reflector-meek.appspot.com"signal-reflector-meek.appspot.com" domain only shows up in the HTTP "Host" header, which is TLS encrypted, and thus not visible to the censors.
$ curl -H 'Host: xss-game.appspot.com' https://www.google.com/
<!doctype html>
[...]
<title>XSS game</title>
This works for all the AppSpot hostnames I tried (even my own), but not for any custom domains.