GitHub: A tag but not a release

GitHub, by default, creates a "release" point when you push a tag (like you can see in my project), but that doesn't mean it creates an actual release.

By default, a tag has one deliverable associated to the tag, and that is the compressed sources of the repo.

Creating a release means associating other deliverables (executables or other binaries) that you may wish to publish under that tag/release.
But you don't have to add any more files (other then the sources) if you don't want to.

So: by default, you don't have any release, only "release placeholders" (one per tag), for you to create a release.

As long as you don't upload a binary to a new release, the tags that you have pushed don't represent a release.

Update

As of 2017-05-31, Github support has stated it's "not currently possible as all tags will appear in [the release] list" - they said they'd pass it along as a feature request, though.

2018-04-17 A "new request on Github community" says it is in the feature request.

2021-10-04: a new public beta of GitHub Releases states:

Tags no longer show in the Release list view

Give our new Releases UI Refresh a look, we changed the default behavior and no longer show tags without releases in the release list

https://github.blog/2021-10-04-beta-github-releases-improving-release-experience/