An important class of bug that this could be used to catch is when the packaging into the tarball goes wrong, even if all the contents are correct. For example this. Unfortunately Github doesn't allow one to test on really exotic OSes (I've had similar problems on Solaris, OpenBSD, and with really old GNU tar) but it's at least a good start, and one could probably adapt this fairly easily to throw code at all kinds of ancient tars.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
An important class of bug that this could be used to catch is when the packaging into the tarball goes wrong, even if all the contents are correct. For example this. Unfortunately Github doesn't allow one to test on really exotic OSes (I've had similar problems on Solaris, OpenBSD, and with really old GNU tar) but it's at least a good start, and one could probably adapt this fairly easily to throw code at all kinds of ancient tars.