I was just looking something up in the online documentation and discovered an error in a link on the Concepts page: at the bottom of the 'Pieces" section, there is the sentence “See the Game Piece for full details of all available traits.” The link to “Game Piece” is broken, having an extraneous pair of < html entities before the “.html” portion of the link.
I did a quick search of the page source and did not find any other instances of this specific error.