Settings > Launcher > "Test pre-releases" (off by default). On, the update
check takes the newest GitHub release that is not a draft and carries a
launcher.json, pre-release or not, in place of the latest full release:
a pre-release newer than the last release is installed, pinned by size
and SHA-256 as any release is. Turned off, the next check goes back to
the latest release, whose files then replace the pre-release's.
- The update notice says "Pre-release" for one, and the log names which
kind of release was taken.
- The changelog shows the release the setting picks, marked as a
pre-release, and is fetched again when the setting changes.
- --no-gui launches follow the same setting.