ProPractice - Web is made as an addon for ProPractice, originally just showed top 10 global elo. I later added more complicated functionally to the point it is now. This was my first project using PHP and interacting a MySQL DB, it was a fun time!
It's a placeholder, it's there to show where something else could go. Why did you want to know about a placeholder? I mean you could of looked at the other projects, but you pick placeholder. You're weird.