Over at the Extensions Working Group, we’re making careful progress toward improvements to the extension ecosystem, aiming to make it easier for all of us to do what we want with extensions: End users and site admins: easier to find, select, and install the right extension; Extension developers: easier to publish extensions and set clearer expectations for support and maintenance, and easier to avoid duplicating existing extensions; Community volunteers: easier to conduct extension reviews and help them get qualified for automated distribution.
As an early step in those improvements, I’d like to point you to the relatively new Extensions Lifecycle documentation, which describes the process of publishing extensions through the CiviCRM ecosystem, along with clear definitions of concepts like stewardship (who’s managing this extension?), project maturity (exactly what is meant by saying an extension is “experimental” or “stable”?), and more.