> Commom UI widgets are not prepared to deal with collections of widely varying sizes.
I don't think there is a standard widget other than what's implemented by each solution. Broot is one way of looking at a volume at the expense of lots of disk reads (for every file on the volume). Ranger does that at a single depth and that's a design choice in Miller's view. nnn doesn't prefer to read within directories unless explicitly requested and that's a design choice too. There's nothing good or bad about these other than a choice to the user to pick the one that fits his use case.
A user always has the liberty to concentrate only on the current directory, just know where he is in the filesystem from the file path and do a fuzzy search to find a file deep in the subtree when he needs to do so. As you might have noticed, even with Broot there's no simple way to list the files marked "unlisted" without navigating to the dir and expanding it. It's a nice program and is a solution to people who likes to see a snapshot of the filesystem in a glance. But would everyone be always interested in the contents of /etc, /run, /usr and /var as shown in one of the sample images?
Anything listed at https://en.wikipedia.org/wiki/Graphical_widget#List_of_commo... does count as "standard widgets". There may be variations in different GUI libraries, but anything that deviates too much from common user expectations will be perceived as broken.
There are ways to avoid traversing the whole volume in each use, namely caching each directory content when it's updated.
As for always showing unwanted information, an interactive solution could allow an option to "fold and hide" specific folders so that their contents are not shown until the user specifically reopens them. A user-friendly interactive solution doesn't require the user to remember and choose among all the available choices for each use, it provides good defaults and reminders on how to access alternative options when those are needed.
I don't think there is a standard widget other than what's implemented by each solution. Broot is one way of looking at a volume at the expense of lots of disk reads (for every file on the volume). Ranger does that at a single depth and that's a design choice in Miller's view. nnn doesn't prefer to read within directories unless explicitly requested and that's a design choice too. There's nothing good or bad about these other than a choice to the user to pick the one that fits his use case.
A user always has the liberty to concentrate only on the current directory, just know where he is in the filesystem from the file path and do a fuzzy search to find a file deep in the subtree when he needs to do so. As you might have noticed, even with Broot there's no simple way to list the files marked "unlisted" without navigating to the dir and expanding it. It's a nice program and is a solution to people who likes to see a snapshot of the filesystem in a glance. But would everyone be always interested in the contents of /etc, /run, /usr and /var as shown in one of the sample images?