Debian and code names

If the code name is meant to be the main version identifier, it should be used everywhere, instead of a strange mix of code names here and version numbers there.

It doesn't help that there is no obvious way to find the correspondence between code names and version numbers. Maybe there's a list on debian.org, but I can't find it. I can find a list on Wikipedia, but shouldn't a project's own website be the primary source of information for such things?

Also, /etc/os-release is a relatively recent addition. For most of Debian's history, /etc/issue is all we had (or lsb_release -d, but that's not in the standard installation).