After comparing several of these directories, seems https://euro-stack.com/ is the most comprehensive. I also like that it allows to filter by both being European and open source.
It is also made by the same people who run https://eurostack.eu/ and who got a lot of visibility delivering the https://euro-stackletter.eu/ letter to President Von der Leyen a year ago. Hopefully they settle soon on what is their primary domain :)
What does the distinction even mean? If an american contributes to a Foss project it is all of a sudden no longer European?
It’s if the project is of european origin or the leading mantainer is european
Is Linux from Finland or from the USA? If someting is open source and has a global contributor base and no single entity can subvert it, then I don’t really think the country matters. But it there is one entity that controls it, then it matters where it is from and what jurisdiction and what policies apply on it.