The `|| true` is often done because people use `errexit` as part of "Bash strict mode"[1], which comes with so many caveats[2] that I usually avoid it. Claude, however, loves it.
Shortened commit SHAs are actually not supported by Actions; if you try, you get
"Unable to resolve action `actions/checkout@11bd719`, the provided ref `11bd719` is the shortened version of a commit SHA, which is not supported. Please use the full commit SHA `11bd71901bbe5b1630ceea73d27597364c9af683` instead."
The Social Radars has an episode where they interview PG, covering much of the history of YC: https://www.thesocialradars.com/episodes (second from the bottom).
[1]: http://redsymbol.net/articles/unofficial-bash-strict-mode/
[2]: https://mywiki.wooledge.org/BashPitfalls#set_-euo_pipefail