Vim. Restore an unlisted buffer

Question

Is there any way to restore an unlisted buffer in Vim and send it back to the list of buffers?

For example:

:ls!
  1# "one.txt"
  2% "two.txt"
  3u "three.txt"

Can I send the third buffer back to the list?

:ls
  1# "one.txt"
  2% "two.txt"
  3  "three.txt"

Answer 1

Switch to your unlisted buffer and reset the 'buflisted' option:

:buf 3
:set buflisted