Apache is both popular and “the place where projects go to die”. They have many, many projects that see limited development activity and aren’t well-known (how many projects in https://projects.apache.org/projects.html?name do you even vaguely know of what they’re about?)

I also think the popularity of the Apache license is part of what makes Apache popular.

> I thought it was the uncool place where stuff was written in Java

They have lots of projects running on the JVM, but “written in Java” isn’t a requirement, nor is “running on the JVM”. See https://projects.apache.org/projects.html?language

I think CNCF is home to most of the big projects I’ve been contributing to or using lately.