The documentation Manage branches says that branches are listed with a collapsable tree view when you're viewing them in Azure.
If your team uses a forward slash separator in your branch names, you'll see a collapsible tree view for those branches.
I find the collapsible tree view a distraction when I'm just trying to find the most recent branch.
How can I view them without the collapsible tree view in Azure Repos, or failing that, is there a way to expand all folders at once?