ubuntu / debian /etc/os-release files - and there was much gnashing of teeth and rending of flesh. . .

Debian Jessie

PRETTY_NAME="Debian GNU/Linux jessie/sid"
NAME="Debian GNU/Linux"
ID=debian
ANSI_COLOR="1;31"
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support/"
BUG_REPORT_URL="http://bugs.debian.org/"

Debian Wheezy

PRETTY_NAME="Debian GNU/Linux 7 (wheezy)"
NAME="Debian GNU/Linux"
VERSION_ID="7"
VERSION="7 (wheezy)"
ID=debian
ANSI_COLOR="1;31"
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support/"
BUG_REPORT_URL="http://bugs.debian.org/"

Ubuntu precise

NAME="Ubuntu"
VERSION="12.04.2 LTS, Precise Pangolin"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu precise (12.04.2 LTS)"
VERSION_ID="12.04"

Ubuntu Quantal

NAME="Ubuntu"
VERSION="12.10, Quantal Quetzal"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu quantal (12.10)"
VERSION_ID="12.10"

Ubuntu raring

NAME="Ubuntu"
VERSION="13.04, Raring Ringtail"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 13.04"
VERSION_ID="13.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"

Here is the Elementary OS version

$ cat /etc/os-release 
NAME="elementary OS"
VERSION="6.1 Jólnir"
ID=elementary
ID_LIKE=ubuntu
PRETTY_NAME="elementary OS 6.1 Jólnir"
LOGO=distributor-logo
VERSION_ID="6.1"
HOME_URL="https://elementary.io/"
DOCUMENTATION_URL="https://elementary.io/docs/learning-the-basics"
SUPPORT_URL="https://elementary.io/support"
BUG_REPORT_URL="https://github.com/elementary/triage/issues/new"
PRIVACY_POLICY_URL="https://elementary.io/privacy-policy"
VERSION_CODENAME=jolnir
UBUNTU_CODENAME=focal

BTW: Nice script to read /etc/os-release from docker images of several linux builds and build table.