Hashtag Performance is a feature thanks to which you can check how the hashtags you’ve chosen are performing and which are providing the most significant reach for your posts.
The graphical chart “The top position reached for a given hashtag” gives you insights about how your post was positioning among the most popular posts with particular hashtag(s), and what was the top position it has reached.
If you can’t see any data here, it means that your post hasn’t reached any high positions for the given hashtag(s).