json-ld/json-ld.org — comment on commit 3c8427bc1b96cbc844d3850fdd4a7f74edcc0f30
File: spec/latest/json-ld-api/index.html line 1469
By gkellogg:

In discussing with Manu, normalization is moved to an external spec based on RDF. That will serialize a result, which will most likely be something in N-Triples like format. In any case, it's really just treated as a blob that is signed.