bury-buffer is an interactive compiled Lisp function in `window.el'.

(bury-buffer &optional BUFFER-OR-NAME)

Put BUFFER-OR-NAME at the end of the list of all buffers.
There it is the least likely candidate for `other-buffer' to
return; thus, the least likely buffer for C-x b to
select by default.

You can specify a buffer name as BUFFER-OR-NAME, or an actual
buffer object. If BUFFER-OR-NAME is nil or omitted, bury the
current buffer. Also, if BUFFER-OR-NAME is nil or omitted,
remove the current buffer from the selected window if it is
displayed there.