[krautsauer]

By license sure, it is. But having a look at https://www.gnu.org/philosophy/free-sw.html.en#four-freedoms I kind of doubt it really is.

Freedom 1 is dubiously fulfilled. I can modify it, sure, but I can't modify it when the program runs on my data for me. Freedom 0 isn't fulfilled. I don't have the necessary input data to run the program myself.

(Of course the free software definition wasn't written for today's world, and the clarification below goes somewhat against my argument for Freedom 0. Feel free to pick this apart.)

[nailer]

That's a fair point, but I don't think anyone was stating it's free software. It doesn't need to meet the four freedoms to be open source, just the open source definition.