How can I tell if a particular distribution of the Discourse client is free software?

[Jagster (Jakke Lehtonen)]

Discourse is open source, so using it is free. Hosting, by own or using CDCK, will cost.

Search is discourse free gave this:

Is Discourse free or not?

Hi everyone, I like how Discourse looks and would like it on my new, tiny personal site if possible. The main homepage for Discourse boldly says “Free” but every link I subsequently follow (like this or this) talks about $10/month on a Digital Ocean server. Is it free or not? Am I missing something here? Thanks if you can help!

@JacobK1

Surely the original discourse GitHub repo isn’t always sufficient, since people may have modified the software before redistributing it?

Sure it is. And de facto the only source to use.