What apps/programs/daemons on OS X use my ~/.ssh/id_rsa* keys? I recently started using Git with GitHub and thus discovered that I already have a generated pair of SSH keys, public and private. This leads me to ask: what applications/programs/daemons on my Mac might have caused this keypair to be created? I've never used SSH to log in to another machine.
Amusingly, your own question includes the answer. GitHub for Mac uses Git via SSH, and will automatically generate unprotected SSH key pairs (e.g. no passphrase) in order to push/pull contents between the remote repo and your local ones.