rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
When I paste this FEN string (position after move 2 of the Sicilian), the NCM board puts an X on c6 indicating an en passant capture is possible on that square.
As far as I can tell, this happens in every position where the last move was a pawn two squares forward.