Twigg

Twigg is a free and open source centralized version control and development platform. Its public description says it is heavily inspired by Google's Critique and Meta's Phabricator, both known for code review and development workflows.

Because the project is open source, its source code can be inspected, used, and modified under its license terms. Centralized version control means a single central repository manages project history. Project details are available at twigg.vc.