GitHub and Gitlab exposes all user's public SSH keys (2019)

Pretty unsafe, I think. And you can't turn it off. https://rushter.com/blog/public-ssh-keys/

Links to APIs:

https://docs.github.com/en/rest/reference/users#list-public-keys-for-a-user

https://docs.gitlab.com/ee/api/users.html#list-ssh-keys-for-user

Public key, by definition, is public. Exposing something that’s public can do very little harm.

Here is more discussion:

https://security.stackexchange.com/questions/150540/is-it-co...

The article (2 years old) explains you could get someone's public keys from github and then compare them with other public keys (they mention on ssh servers) to see if a person is using the same key elsewhere.

The argument boils down to the fact that ssh will also give you a list of valid public keys.

It doesn't seem very critical to me, and anyone who is worried could just use a different key for github which is good practice anyway imo