I’ve noticed that lots of accounts that post dismissive, low-content comments like yours have an “about“ section in their user profile that matches the exact format of

about:

[ my public key: https://keybase.io/<Hn profile name>; my proof: https://keybase.io/<Hn profile name>/sigs/n_-<text matching [a-zA-Z0-9]+> ]

Complete with the opening and closing brackets.

Why is that?