Nope, these are the public keys of my fediverse account on nostr in hex form.

It's difficult to differentiate public and private key representations in hex, that why using the bech32 string representation starting with "npub" or "nsec" is better for us human. https://github.com/nostr-protocol/nips/blob/master/19.md

But the protocol is working with the hex form.

The fediverse-nostr bridge mostr.pub generates and associates a nostr key pair.

Here, the public key associated with my fediverse account had changed, and I was giving the data to Alex in case he needed it to track the bug.

Your question has made me realize that I don't have access to the private part of the keyset generated by the bridge. So I have no risk of leaking it by mistake.