Those are your SSH keys. SSH keys are used for user authentication are usually stored in the user’s .ssh directory under the home directory. However, in enterprise environments, the location is often different. The default key file name depends on the algorithm, usually it’s idrsa when using the default RSA algorithm. It could also be, for example, iddsa or id_ecdsa.
Here is a bit more information about
ecdsa - a new Digital Signature Algorithm standarized by the US government, using elliptic curves. This is probably a good algorithm for current applications. Only three key sizes are supported: 256, 384, and 521 (sic!) bits. We would recommend always using it with 521 bits, since the keys are still small and probably more secure than the smaller keys (even though they should be safe as well). Most SSH clients now support this algorithm.
ed25519 - this is a new algorithm added in OpenSSH. Support for it in clients is not yet universal. Thus its use in general purpose applications may not yet be advisable.