Release
A named, versioned snapshot of software made available to users, like version 2.1.0.
What it tells you about a developer
A repository history with real tagged releases proves the developer carries work to a published finish line rather than leaving it unfinished.
A release marks a point where software was packaged and published, with a version number and usually notes describing what changed. On GitHub, a repository's releases are listed publicly. Disciplined versioning across releases is a hygiene habit that maintainers of serious projects develop.