Oh, I had not thought to look in the settings for the opening explorer until today. I knew it had the database of master's games, but didn't know you could explore games played on lichess and filter by rating. Learn something new all the time.
Our website is designed to be a more general viewer for these interesting chess datasets, although our main database is the Lichess one because of its size, we do also have other datasets from tournament games, and from chess engines playing against each other. We are not directly associated with Lichess.