Wayback spotted some of it, but after bouncing through its 302 capture one ends up here, but yes, the actual repo is still gone and the "in page" snapshot doesn't render the actual pdf:

https://web.archive.org/web/20220917133741/https://github.co...

Also, after some url surgery it seems Wayback did grab the .tar.gz of a release <https://web.archive.org/web/20201226113237/https://codeload....> but sadly it does not include the pdf, only some .png and a helpfully named "Software/blank", and also an "asset" of ChessOracle1.2.zip containing the .h5 weights but no pdf to be seen