The old jsloader.js is replaced with moduleConfig.json to make the config pure and support tools like cocos-console better.
All the modules of Cocos2d-html5 is configed here. If you need some modules in your project, just config the names in modules of project.json.
The config of each module is an array which includes module name or javascript path, like:
"menus" : [
"core", "actions",
"cocos2d/menus/CCMenuItem.js",
"cocos2d/menus/CCMenu.js"
]
This means menus requires core and actions, and has cocos2d/menus/CCMenuItem.js and cocos2d/menus/CCMenu.js.