The git.io link in at least the first paper that comes up on your search (https://git.io/sosr15-int-demo https://git.io/sosr15-int-demo) appears to have been ar

The git.io link in at least the first paper that comes up on your search (https://git.io/sosr15-int-demo https://git.io/sosr15-int-demo) appears to have been archived by archive.org, which shows the redirection and then follows it to the archived version of the final github page. I don't know how common it is for these links to have been caught by the archive, but potentially all is not lost.