This directory contains bootstrap source tarballs for the Hadrian build system used by GHC.
For each GHC release, a subdirectory is created.
Within this subdirectory, GHC version strings in the tarball names refer to the bootstrap compiler used to compile the GHC release.

See: https://gitlab.haskell.org/ghc/ghc/-/tree/master/hadrian/bootstrap for more information on how to create these tarballs.