I know that not many here are computer savvy, but I use qpdf and ocrmypdf in tandem to strip and rewrite metadata from PDF files and store them in PDF Type-A format.

https://en.m.wikipedia.org/wiki/QPDF

https://ocrmypdf.readthedocs.io/en/latest/index.html

I kind of assume this with any digital media. Games, music, ebooks, stock videos, whatever - embedding a tiny unique ID is very easy and can allow publishers to track down leakers/pirates.

Honestly, even though as a consumer I don't like it, I don't mind it that much. Doesn't seem right to take the extreme position of "publishers should not be allowed to have ANY way of finding out who is leaking things". There needs to be a balance.

Online phone-home DRM is a huge fuck no, but a benign little piece of metadata that doesn't interact with anything and can't be used to spy on me? Whatever, I can accept it.