Ubuntu – File ownership in debian packages

These files are part of the debian-cd package, which is used to build the Ubuntu live CDs.

The images are sourced by an include file named README.html.in, which the add-bin-doc tool incorporates into README.html at the root of the CD's filesystem. This file is either never generated or is deleted from Ubuntu's CDs, so I believe the images are unused.

You can find the Debian version on which your Ubuntu version is based in the file: /etc/debian_version

From 10.04 up to 21.04:

Ubuntu            Debian  
21.04  hirsute    bullseye/ sid   - 11
20.10  groovy     bullseye/ sid
20.04  focal      bullseye/ sid
19.10  eoan       buster  / sid   - 10
19.04  disco      buster  / sid
18.10  cosmic     buster  / sid
18.04  bionic     buster  / sid
17.10  artful     stretch / sid   - 9
17.04  zesty      stretch / sid
16.10  yakkety    stretch / sid
16.04  xenial     stretch / sid
15.10  wily       jessie  / sid   - 8
15.04  vivid      jessie  / sid
14.10  utopic     jessie  / sid
14.04  trusty     jessie  / sid
13.10  saucy      wheezy  / sid   - 7
13.04  raring     wheezy  / sid
12.10  quantal    wheezy  / sid
12.04  precise    wheezy  / sid
11.10  oneiric    wheezy  / sid
11.04  natty      squeeze / sid   - 6
10.10  maverick   squeeze / sid
10.04  lucid      squeeze / sid

sid is the development distribution of Debian (sid - testing - stable)

You can find out the contents of the file without installing an entire system by view the sources for the package basefiles on Launchpad.