I haven't figured out how to determine which major OS release you're on, but we can certainly look into Homebrew core to figure out how they do it for MacOS. Once that's determined, we can then see how we can translate that to Windows and Linux. So yes, it'd be nice to solve this problem. For now the assumption is only the latest major OS releases are supported: Windows 10, High Sierra and... w/e flavour of Ubuntu/Debian is the latest.

If I'm reading the code right, the assumption is that the latest version of Homebrew supports bottles compiled on High Sierra by default, but there is no system in place to determine the underlying major OS release Homebrew is running on. That is configured separately through $HOMEBREW_MACOS_VERSION (or $HOMEBREW_OSX_VERSION for backwards compatibility), likely configured through the install script. That doesn't seem too hard to implement if someone wants to take a crack at it :)

Neat! There is a CLI tool available to determine the equivalent of /etc/os-release on Mac. and they do seem to be utilizing it in the install scripts. This does seem do-able. https://github.com/Homebrew/brew/blob/bbbd6d86b8885e4f5fc8ea10fd531fe91a2f5ec7/Library/Homebrew/brew.sh#L85-L86

><> cat /etc/os-release
cat: /etc/os-release: No such file or directory
><> sw_vers -productRelease
10.13.4