The problem for me is rounded corners which tangent the square content they outline in list view, especially at small sizes. The content is square, if you put rounded corners around it you need additional padding, which is not desirable. It also is strange not to highlight an entire row when the information is laid out in rows. I have no issue with the basic design choice in grid view.
When I say tangent, I am referring to how the outline goes uncomfortable close to the corners of square icons.
However, as somebody who mostly navigates by keyboard, I don’t understand why we need two different types of selection (the outline (previously underline) and the highlight). It makes it confusing in cases such as selecting files by holding shift and using arrow keys. I constantly mistake one kind of selection for another and try to select multiple files using this method and am confused why it doesn’t work. Another example is knowing which file is being referenced in the info panel, whether it is the selected file or the folder being viewed. When I go up a level and there is an underline/outline around the directory I came from, I frequently forget that the info panel is showing info for the directory and not the selected item. I look to the info panel and get wrong info, or add tags/ratings/comments to the wrong directory.
There should be one kind of selection, the highlight, and if there is some accessibility case I am not aware of where an outline is necessary visually, then the outline too should always be there, with option to disable, probably disabled by default. In some cases you would cause a functional change, e.g. that example going up a level would result in the directory you just came from selected instead of just outlined, and the info panel would show that, but I think that is a lot clearer – there would be a selected item and the info panel would show that, and you could press escape or click blank space to deselect the item and get the info panel to show info about the directory you are viewing.
As far as I understand it the reasoning behind it is to know what file will be selected if you press arrow keys, but I don’t think that is particularly helpful. The moment you press an arrow key it jumps into the other kind of selection anyway and you find out. Also, you know the first item is going to be selected. And, I still think there are better ways of making that clearer visually (the underline was definitely not sufficient), one of which is to just properly select (highlight) in more cases, but also I would say, in list and compact views, an outline around just the name of the files, and paying attention to how any rounded corners look at different sizes, would be preferable.