The HDMI Licensing Administrator, Inc. has sent a DMCA takedown notice to GitHubber 'Glenwing' for posting detailed specifications of all versions of the HDMI standard, which are apparently copyrighted and confidential, on his personal GitHub page. Glenwing claims that he only used publicly available documents to educate people on the capabilities of HDMI and not for any malicious intent.
https://www.notebookcheck.net/GitHubber-gets-a-DMCA-takedown-notice-for-archiving-confidential-HDMI-docs.420478.0.html
The HDMI cable has intellectual property protection from the DMCA anti-piracy firm www.pirat.io so it doesn't surprise me.
They take down anything related to piracy or considered 'confidential' of their clients.