_s (Underscores)

_s (Underscores) is the starter theme that defined how a generation of WordPress developers thought about theme structure. Automattic generated 100M+ underscores-based sites. The repo was archived in September 2025 with a redirect note to the new themeshape project. The 10.9k stars reflect its historic impact, not current usage. If you have an existing WP site built on _s, the archive notice tells you to migrate manually. The code is still solid PHP 7+ WordPress theme boilerplate. The maintainers (Tammie Lister, Ian Stewart) both moved on to other roles. Anyone who rescues it would have to decide: keep the WP-only scope, or modernize the whole thing (block themes, full-site editing, the works).