Package

Was just looking around this evening trying to figure out how the package.json works and not really sure i understand what is going on. for instance it seems to have "locals", "partials", and "url" available under "views". Is that it? Also it appears that you can set up stuff that will show up in the template editor via package.json. How does that work? Also, curious how partials work in the context of views (pages). I see in the latest templates you're always referencing them as {{>partialname}} but in some the older templates they are referenced either as partials or as variables. (was fooling with Marfa). Can it work either way as it seems it can and its just a convention thing? Sorry a lot of questions :) But I'd love a more in-depth idea of how everything fits together in that file.