That’s not a takedown notice and does not allege that the repo is infringing any RIAA copyright. They are alleging instead a violation of the anti-circumventio

That’s not a takedown notice and does not allege that the repo is infringing any RIAA copyright. They are alleging instead a violation of the anti-circumvention provision of DMCA which is not covered by takedown notice procedure. The letter is also missing several required elements of a takedown letter which makes sense because it’s not a takedown notice nor does it purport to be one. It’s just a letter making demands that cites the DMCA. It carries no legal weight other than the implied threat of a lawsuit.