Variable: tar-data-buffer
tar-data-buffer is a buffer-local variable defined in tar-mode.el.gz.
Documentation
Buffer that holds the actual raw tar bytes.
Source Code
;; Defined in /usr/src/emacs/lisp/tar-mode.el.gz
;; The Tar data is made up of bytes and better manipulated as bytes
;; and can be very large, so insert/delete can be costly. The summary we
;; want to display may contain non-ascii chars, of course, so we'd like it
;; to be multibyte. We used to keep both in the same buffer and switch
;; from/to uni/multibyte. But this had several downsides:
;; - set-buffer-multibyte has an O(N^2) worst case that tends to be triggered
;; here, so it gets atrociously slow on large Tar files.
;; - need to widen/narrow the buffer to show/hide the raw data, and need to
;; maintain a tar-header-offset that keeps track of the boundary between
;; the two.
;; - can't use markers because they're not preserved by set-buffer-multibyte.
;; So instead, we now keep the two pieces of data in separate buffers, and
;; use the new buffer-swap-text primitive when we need to change which data
;; is associated with "the" buffer.
(defvar-local tar-data-buffer nil
"Buffer that holds the actual raw tar bytes.")