a .deb file is an ar archive containing two .tar.gz files, one of which (data.tar.gz) contains the binary along with required files under the same paths you would install on your system.

This example from tldp.org will help:

  ------------------------------------

  $ ar tv parted_1.4.24-4_i386.deb
  rw-r--r-- 0/0      4 Mar 28 13:46 2002 debian-binary
  rw-r--r-- 0/0   1386 Mar 28 13:46 2002 control.tar.gz
  rw-r--r-- 0/0  39772 Mar 28 13:46 2002 data.tar.gz

  The 'data.tar.gz' file contains all the files that will be
  installed with their destination paths:

  drwxr-xr-x root/root         0 2002-03-28 13:44:57 ./
  drwxr-xr-x root/root         0 2002-03-28 13:44:49 ./sbin/
  -rwxr-xr-x root/root     31656 2002-03-28 13:44:49 ./sbin/parted
  drwxr-xr-x root/root         0 2002-03-28 13:44:38 ./usr/
  drwxr-xr-x root/root         0 2002-03-28 13:44:41 ./usr/share/
  drwxr-xr-x root/root         0 2002-03-28 13:44:38 ./usr/share/man/
  drwxr-xr-x root/root         0 2002-03-28 13:44:52 ./usr/share/man/man8/
  -rw-r--r-- root/root      1608 2002-03-28 13:44:37 ./usr/share/man/man8/parted.8.gz
  drwxr-xr-x root/root         0 2002-03-28 13:44:41 ./usr/share/doc/
  drwxr-xr-x root/root         0 2002-03-28 13:44:52 ./usr/share/doc/parted/
  -rw-r--r-- root/root      1880 2002-03-07 14:20:08 ./usr/share/doc/parted/README.Debian
  -rw-r--r-- root/root      1347 2002-02-27 01:40:50 ./usr/share/doc/parted/copyright
  -rw-r--r-- root/root      6444 2002-03-28 13:37:33 ./usr/share/doc/parted/changelog.Debian.gz
  -rw-r--r-- root/root     15523 2002-03-28 02:36:43 ./usr/share/doc/parted/changelog.gz