Maybe worthless but there's an xml header in the file
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="XMP Core 5.4.0">
<rdf:RDF xmlns:rdf="http ://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about=""
xmlns:tiff="http ://ns.adobe.com/tiff/1.0/">
<tiff:Orientation>1</tiff:Orientation>
</rdf:Description>
</rdf:RDF>
</x:xmpmeta>
(large one only that I can see)
I've exhausted all ideads I had on it. Other than taking a look at the w3 specification link on it has mention of owls
https:// www.w3.org/1999/02/22-rdf-syntax-ns#
@prefix owl: <http ://www.w3.org/2002/07/owl#.
@prefix dc: <http:// purl.org/dc/elements/1.1/.
<http ://www.w3.org/1999/02/22-rdf-syntax-ns#a owl:Ontology ;
Interesting:
https: //www.w3.org/2002/07/owl#
Refs:
https: //www.w3.org/OWL/
Overview:
The W3C Web Ontology Language (OWL) is a Semantic Web language designed to represent rich and complex knowledge about things, groups of things, and relations between things. (first line only - go ahead and do your own further reading if you find it useful)
This is an object-relational mapping specification - how to read the map! (?)
Anyway it's been a long ass day. someone else can dig if they think this is useful.