That is what I would mean by “open source” but I can’t blame the uninitiated from thinking it means something else. Consider every-day usage of the word “open” - an open door could be fully open, just have a small gap or even shut but unlocked (“come in, the door is open”). A well-meaning developer could think Unreal engine is open source because they can see the source code (the code is “open” to them). Words don’t have innate definitions, they have usages.