Holy shit. Sluicebox just blew the doors to the Sierra kingdom wide open. This is a game-changer for anyone who's ever tried to poke around in or modify old Sierra SCI games.
Check out OneShortEye's video for a brief explanation: https://youtu.be/zi5sFqd-YYg
Or go straight to the source: https://www.benshoof.org/blog/sci-scripts