Why don't these people/companies think about how hard it will be to search for their $thing !?
https://atproto.at/robots.txt is good and findable with a direct search
https://atproto.wiki/robots.txt is empty but findable on Google.
https://pulsar.feeds.blue/robots.txt is 404 and thus not indexed by Google.
https://leaflet.pub/robots.txt is good. A logged in google search for this finds this for me.
Tell the people at https://pulsar.feeds.blue to fix their robots.txt if they want to get indexed.