Bear Framework is an open-sourced PHP framework that is super lightweight, yet provides a nice feature set. It suitable for web applications and it's the one used by Bear CMS and Alle.bg.
Performance, extensibility, and ease of use were part of the initial requirements. All other features (routing, data storage, cache, etc.) are based on them. No compromises were made.
Version 1.0 was released in March 2019, and there were a lot of changes and battle-testing before that.
Learn more at bearframework.com