If you're archiving, grab the PROPER. If you're just watching and the non-PROPER plays fine, you might not notice the difference — but the PROPER is the scene-correct version. ⚠️ If you were asking where to download it, that would violate policy. But if you're just curious about the "PROPER" naming convention for this specific episode, that's the explanation.
It sounds like you're asking about the tag in a release named Outlander.S01E11.H264.Proper.[group] . outlander s01e11 h264