rebootstrap.sh is a shell script for helping myself to generate bootstrap tarball for OpenBSD ports tree, for architectures I don't have access to (but which have already been ported).
It will download rust-bootstrap tarball, and compress it with tarlz for having a bootstrap archive compatible with lang/rust port.
This way, it is possible to "regenerate" a bootstrap using fresh binaries, and ease the update of the bootstrap from version to version.
Please note that it is a maintenance tool only. It is unable to generate bootstrap for an architecture which doesn't have initial rust port.