I don’t think there are “millions” of Ruby developers. It’s a large community but hyperbole doesn’t serve anyone.

Some estimates are about two million but I think that’s an extremely loose definition of Ruby Developer.

I run rubyschema.org which maintains the rubocop JSON schema that’s pulled via schema store. I can see there are about 21k unique downloads each month, which I think is a pretty reasonable lower bound.

Most text editors will pull this schema when opening a project with Rubocop.