There is also a lot of indirect funding in the form of the governments purchasing habits: https://blog.documentfoundation.org/blog/2024/04/04/german-s...
In the EU the size of the state is often bigger than 50% of GDP. What the government buys is very important and means a lot of $$ for projects, consultants and the rest of the open source ecosystem.
Except for the fact that big consultancies who receive most of the government contracts, have zero contribution to the open source ecosystem.
It's basically an SQL wrapper around poppler.