Comment by burnhamup
2 days ago
I poked at the Steam Depots for some of these games for more information. A game like Putt-Putt ships the ScummVM under the GPL license and runs it with the original asset files: https://steamdb.info/depot/294661/
Backyard Baseball does not appear to be using ScummVM. https://steamdb.info/depot/3170541/
The .he* files also appear to be the original assets for the game. And then they built a Scumm interpreter to run the game which can talk to Steam to use leaderboards and achievements.