https://www.reddit.com/r/freebsd/comments/1ty5njr/pkgbase_major_upgrade_from_freebsd_144_to_151rc2/
This upgrade blended:
part of the official announcement for 15.1-RC2 – altered for compatibility with the major upgrade
part of Emrion's https://forums.freebsd.org/posts/762515 – adapted for my preferred shell, /bin/tcsh.
…
Packages for the third release candidate, RC3, were not available at the time.
