fetching external context on framing

[tisdall]

I'm still trying to understand many aspects of JSON-LD so I apologize for my ignorance...

I'm trying to restructure JSON-LD documents to simplify processing and have chosen to use frame. I noticed that when I use it that it uses request to make calls to fetch https://schema.org/docs/jsonldcontext.jsonld (and it does it twice and seems to be redirected to that from http://schema.org/ which is the @context for the 2 objects). Why does it need to fetch that file to do the framing? Also, is there a way to prevent the call by providing my own context or something else?

The frame I'm using is simply {}. I found #70 and #85 so I suppose I'll just define my own method to use a local copy, but I'd still like to understand