https://github.com/duplicati/duplicati/branches/all shows the branching scheme. I’m not very familiar with GitHub, but have worked in environments that had release branches. You can see Duplicati’s branches, however one difference from my large-company experiences is that Duplicati tries not to handle multiple branches concurrently (which is complex even with tools to help place a given change in many at once).
The branch creation does allow additional changes to continue in master and Canary without bothering release branches, but the usual goal is for a quick ship rather than a lot of parallel branch maintenance. The release branch start could be earlier, but then its change management becomes more complicated.
https://github.com/duplicati/duplicati/commits is the flow of Duplicati commits. There are probably some techniques for reducing tracking, decisions, and movement to a tolerable level. I don’t know specifics…
If you have ideas on how to do this a bit better for a small resource-limited volunteer project, please say.