Publickey agent specification being loaded as private key

I use an agent which holds many private keys and specify which private key to use for which remote by specifying IdentityFile <key path>.pub per host in my ssh config. This setup appears to be currently broken or unsupported with sshfs. For example:

Given an ssh config:

Host myhost
    Hostname myhostname
    IdentityFile ~/.ssh/mykey.pub

and a minimal example:

import fsspec
with fsspec.open("ssh://myhost/myfile.txt") as f:
    f.read()

Gives the following traceback:

log.txt

It's not immediately clear to me whether the issue is here or in asyncssh

Start by reproducing the minimal fsspec.open example with the provided SSH config and inspect log.txt. Trace how sshfs handles the IdentityFile ending in .pub and determine whether the behavior belongs in sshfs or asyncssh; done means the agent-based public-key configuration works or its unsupported status is clearly established.