The NAF format is linguistic annotation format designed for complex NLP pipelines. NAF combines strengths of the Linguistic Annotation Framework (LAF) as described in Ide et al. (2003) and the NLP Interchange Format (Hellman et al. 2013, NIF). Its layered extensible (LAF-based) structure makes it easy to use in NLP architectures. NAF uses URIs extensively and can be converted to RDF-NAF, an alternative representation that can be read by RDF parsers. This provides interoperability and a straightforward way to model provenance as also found in NIF.
The full specification of NAF can be found in GitHub: