mattias
Actually I forced the change on the Dutch translation to drop the vendor folder. The reason for this is that each of these translations had been cloning the French repository, which also included the generated vendor folder. This folder is generated using composer and includes a - so called - autoloader file with a random name, because all of these languages had been duplicating that file, none could work next to the other.
In order to fix this you can manually run composer dumpautoload in the extension directory, or you can ask the author @rodymol123 of the translation to use a proper release script (like the one i used).
As Qiaeru points out though, almost everything about translations will change in the upcoming beta (3), so it might be wise to wait for that.
