My use case is a provisioner, in which arbitrary names (e.g. "avahi") is mapped to the OS proper package name (e.g."avahi-daemon"). Since the name depends on the OS version, I do need to know. Which I currently do with a mix of lsb_release (damn slow on Debian) and OS-specific heuristics. That is precisely one use case for os-release.
Debian does provide a version name for Jessie, either as 'unstable', 'sid' or 'jessie/sid', as reported by lsb_release and contained in /etc/debian_version. I don't understand the rationale behind not putting the same in os-release as the whole point of os-release *is* to identify what a tool/script is running on. A useful value for testing would e.g. be VERSION -> future version number (future version number/sid) VERSION_ID -> future version number which matches what fedora does with rawhide Sylvain
