The porposal is to utilize QSortFilterProxyModel for sorting and filtering.
When working with on a bigger project with multiple branches some means to find a desired branch for switching or creating a new branch may be considered helpful.
So I added a line edit and a QSortFilterProxyModel to do that for me.
Additionally: new branches are currently appended. Though this makes them easy to find, I think it's counter intuitive and a tad ugly. While the sort mechanism of the Proxy does not help initially, it does upon adding branches.
Drawback: the line edit for filtering may be associated with the "New" button by users. This could make the workflow for that less intuitive.