Ok 
I suspect Github-account-over-Tor still works, no phone number required, like this:
- Whonix VM
- Choose an onionmail.info server from here and follow directions for creating a new account: OnionMail public server list.
- Configure Thunderbird to use the account w/ the hidden service domain you chose
- Create a new account on Github, with the blah@onionmail.info alias as your address (i.e. not the
blah@alphanumericalphanumericalphanumeric.onion‘true’ account) - Do not add a phone number
- Check your mail on Thunderbird and verify the account
- Done.
If this does indeed still work, perhaps it only works because onionmail.info is not a big enough email provider for Microsoft to have clocked it’s a frontend for torified email. Or perhaps they don’t care (yet). But I bet it still works.