Links from the achievements popup (privileges and badges) on the top bar refer to the FAQ page on [Area 51][1]:

> [![FAQ][2]][2]

This is probably a stub for privileges, but the badges page exists on Area 51 (see the proper link on the right side of the screenshot).

  [1]: https://area51.stackexchange.com/
  [2]: https://i.sstatic.net/Ru9FR.jpg