No, this is not a reference to the HAL 9000 from from Clarke's 2001: A Space Odyssey,
Quick Answer
HAL is an acronym for Hypertext Application Language and is designed to provide "...a set of conventions for expressing hyperlinks in either JSON or XML." HAL is a IANA registered media type that enables RESTful APIs to return JSON (or XML) content with hypertext (aka hypermedia) that can be consumed by machine agents and easily interpreted by human agents. Because it is a registered media type, developers can specify application/hal+json
as the value for the Content-Type response header.
Digging Deeper