I am not sure of the full history but all of Dreamsource Labs changes are on Github (since ~2014) and they are updating DSView and working on any issues people report via GitHub issues.
The first version they released was just an archive file of their version based on some version of Sigrok. That version was then uploaded to Github. That version is not in any way related to the Sigrok git repository, like would happen if you forked it through Github. So no, this does not contain their changes. It contains their version, and good luck figuring out which Sigrok version that is against. None of the automated git merge / cherry-pick / rebase commands are going to be of any help. While I imagine this complies with the license, it's certainly behaving like a bad guest. If you behave like a bad guest, don't be surprised you don't get invited to the next Christmas party.
Regardless of the motivation of the Sigrok developers, clearly the DSLogic are a bad choice if you search something compatible with Sigrok. If their own custom software is fine for you, then it may be an option.
I bought the first version, saw the horrible cross-talk on the flying leads, the hacked state of the software which was clearly not going to be integrated in the Sigrok project, and I threw it in a drawer and decided not to spend any more effort and energy on it. The Saleae Logic was more expensive, but was worth the hassle-free operation for me.