Pharo uses libgit2 binding and adds nice tools on top of it. The development of Pharo itself is based on Git/Github. So it uses standard Git workflow with branches, pull-requests, CI building and testing etc., but because it has methods based granularity, it is even better than plain Git for operations like merging and cherry-picking (it can, for example, easily resolve conflicts that plaintext based Git cannot). Moreover, it allows things like listing the history of a particular method. Even CI building can benefit from still-present image capabilities because you can have a basic prebuild image with project dependencies and then just load what you are really interested in in a few seconds (while still having an option to bootstrap it completely).
