The DMCA notice linked on the page [1] gives a few more details.

We have received information that the domain listed above, which appears to be on servers under your control, is offering unlicensed copies of, or is engaged in other unauthorized activities relating to, copyrighted works published by Pearson Education, Inc.

    Copyright work(s):

Deep Learning with R 9781617295546 Algorithms 9780321573513

Copyright owner(s) or exclusive licensee:

Pearson Education, Inc.

    Copyright infringing material or activity found at the following location(s):

https://github.com/jjallaire/deep-learning-with-r-notebooks https://github.com/kevin-wayne/algs4

[1] https://github.com/github/dmca/blob/master/2021/04/2021-04-2...

Kevin Wayne is one of the authors of Algorithms 4th ed. by Robert Sedgewick and Kevin Wayne and he has a github repository called "algs4". Pearson sent github a DMCA notice for this repository and another. I'm not sure exactly what content he hosted in "algs4".