The large list box in the Pageant main window lists the private keys that are currently loaded into Pageant. The list might look something like this:
ssh-rsa 2048 22:d6:69:c9:22:51:ac:cb:b9:15:67:47:f7:65:6d:d7 k1
ssh-dss 2048 e4:6c:69:f3:4f:fc:cf:fc:96:c0:88:34:a7:1e:59:d7 k2
For each key, the list box will tell you:
ssh1
(an RSA key for use with the SSH-1 protocol), ssh-rsa
(an RSA key for use with the SSH-2 protocol), ssh-dss
(a DSA key for use with the SSH-2 protocol), ecdsa-sha2-*
(an ECDSA key for use with the SSH-2 protocol), or ssh-ed25519
(an Ed25519 key for use with the SSH-2 protocol).
ssh-keygen
when applied to your authorized_keys
file.