Unloaded buffers and the :ls! command

Question

I ran :ls! (having only a vague memory of the command and not really knowing what I was going to see) and saw a short list of files (maybe 5 or 6) with 'u' in the gutter. Apart from one of the files, all were from months or years ago.

I understand the 'u' means they are 'unloaded' buffers. Somewhere I read you can get rid of them with :bwipeout. So I did that. They disappeared from :ls!.

However, shortly after, another file appeared in the :ls! list with 'u' in the gutter; a file I think I closed normally. However, other files I've been editing and closing normally like the latter did not appear in the list.

What's going on? Why did this file, in no way different from other files I've been editing, appear in the :ls! list and others not?

And why are buffers in vim so extraordinarily convoluted? Is there a post anywhere that is able to explain buffers in a short, sweet way?

Answer 1

I would go for :h :ls for an explanation.

In short, :ls! shows also unlisted buffers (:h unlisted-buffers) also available as a link from :h :ls:

                                                *unlisted-buffer*
unlisted        The buffer is not in the buffer list.  It is not used for
                normal editing, but to show a help file, remember a file name
                or marks.  The ":bdelete" command will also set this option,
                thus it doesn't completely delete the buffer.  Settings: >
                        :setlocal nobuflisted

If you are sure that buffers you see there were wiped out, not deleted, then I would think of a plugin that set nobuflisted for the buffer(s).