That error seems like it was coming from a malformed package.json file. Could you please check if the game's package.json has any issues on it? You'll be able to see it clearly with a code editor like Visual Studio Code.
You could be right, though it appears to be something to do with the cooktool altering the original.
Both versions load fine in vscode, but the post-build version is all on one line and has additional info from your "Customization" section.
Before:
{
"name": "rmmz-game",
"main": "index.html",
"chromium-args": "--force-color-profile=srgb --disable-devtools",
"window": {
"title": "Merauders",
"width": 1280,
"height": 720,
"position": "center",
"icon": "icon/icon.png"
}
}
After:
{
"name": "rmmz-game",
"app_name": "My New Game",
"version": "1.0.0.0",
"main": "index.html",
"chromium-args": "--force-color-profile=srgb --disable-devtools",
"background": false,
"js-flags": "--expose-gc",
"nodejs": true,
"window": {
"width": 1280,
"height": 720,
"icon": "icon/icon.png",
"id": "",
"min_width": 0,
"min_height": 0,
"title": "Merauders",
"resizable": true,
"fullscreen": false,
"kiosk": false,
"position": "center"
}
}
From what I can see, they are correct. I don't see anything that would trigger a malformed manifest error.
A similar error that I noticed (and now fixed) is that the bootstrap would attempt to load the FileCatalog.sbfc when it's the first time that the game boots. So, if you have strict cache checking on or disabled the option to clear the cache when the game closes, check out the update.
If not, feel free to send me a build of the game so I can diagnose it.