Multiple programs go by the same name "Cinelerra" for the same purpose (non-linear editing on Linux). The submitted link directs to the original (?) one.
I like that the author gives a detailed step-by-step process with caveats on the way along. However, I believe it is slowly improving. Namely, there is an online service (https://online-verfahren.notar.de/ov/home) that may somewhat ease the process (steps 2–4 & 8).