Update
Ran into this again today - when my work laptop was taken home - appears that a Window domain might be the underlying issue. Found the soluti
Seems like you have a bunch of private keys:
debug1: Trying private key: /p/.ssh/identity
debug1: Trying private key: /p/.ssh/id_rsa
debug1: Trying private key: /p/.ssh/id_dsa
Do you recognize any of these?
You might try to specify the key to be used with -i:
ssh -i /path/to/key -vT git@github.com
Maybe this will help.