Offer breadcrumbs navigation buttons in the headerbar to show hierarchy, instead of showing it in the contents area?
When I look at this:
I find that the path hierarchy links just above the main title lack visual distinction somewhat, and therefore feel like noise. Yet, at the same time, I see the headerbar above that does not do much more than repeat the main title that is shown at the top of the page... so, could we do something more elegant with this?
I'm thinking a pathbar headerbar made of breadcrumb buttons (or however you'd call them), like Nautilus:
That way, you could have the page contents start cleanly with the title.
Now, I see there are some weird situations where there are multiple hierarchical paths sometimes:
...but after thinking about it, it's not really that big of an issue if you provide the "dropdown" popover choice thingy, like Nautilus' breadcrumbs bar does with the last level with the "▼" downwards pointing triangle, so that you could handle multiple paths within the same widget... and to avoid repeating the title, you could just use "Current page" for the last item level.
So, in this example, the breadcrumbs pathbar headerbar could be:
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