I really like its format over Dolphin’s, I find it much more intuitive. It shows the whole filetree from root and double clicking a folder just expands the it further. This is different than how Dolphin works, which only shows one folder at once like how Windows does in the main windows of File Explorer.
I think I might be autistic.
Specifically qBittorrent used with Debian and KDE. Not sure of it looks different elsewhere.
I think you’re referring to the “file picker” window. i think qBittorrent is using Dolphin as the file picker and as everyone else commented already you can get the same behavior if you use the “Details” view. Go the settings on Dolphin and tick the Expandable option
Alternatively, you can add the Folder panel (F7) and have the same functionality while having a “Compact” or “Icons” for the files