What features would you like to see in ChessViewer?

[BilgeGates]

ChessViewer currently covers board editing, FEN tooling, and high-quality export. A few things I've been thinking about adding:

• Square highlighting and arrow overlays (#161)
• Custom and fairy piece sets — user upload, themed sets (#162)
• FEN extraction from board images (#163)
• PGN export (#164)
• LaTeX export for skak / chessboard packages (#165)
• Embed code — generate an iframe snippet to drop a position on any site (#166)

What would actually be useful for you? If you have a concrete use case, describe the problem — that's more helpful than a general feature request.