Github/Atlassian is really two or three separate things. It's the DVCS hosting piece firstly. Secondly it's the repository/branch/tag browser interface which includes tickets, PRs, PR commentary, and merge history, wiki, release tracking/downloads, and other minor features like fork-tracking/browsing. The third feature, which often is completely separate, is the build server which could also be distributed (maybe cryptographically verifiable?) and the build-success/failure could conceptually be monitored/linked into the general interface and posted against the project.