You can still download the repo off archive.org
https://web.archive.org/web/20211231094826/https://github.co...
Click the green Code button, then Download ZIP.
One can also get the commit from github itself.
Also, see https://news.ycombinator.com/item?id=29932282 for a newer hash.
# clone the old repo noDRM/DeDRM_tools forked from
git clone https://github.com/apprenticeharper/DeDRM_tools
cd DeDRM_tools
# fetch the commit hash archive.org tells us about:
git fetch origin 8c819c71376ab76445dd79d5cf2b28b6c0c2819e
git checkout -b noDRM FETCH_HEAD