common qualifiers

[jlb-bb]

It is useful to define (purl-wide, as opposed to type specific) common qualifier keys and values such as OS, architecture, GUI framework. It would improve automated consumption of purls.

[iamwillbar]

One challenge is that these aren't truly common, their existence (or not) and specific definition (such as the values used) will differ across package managers. purl needs to retain the values needed to communicate with the actual package manager, and mapping values to common values wouldn't allow that.

We could have a best practice of using "common keys" when defining new types and pull these common keys into a separate section and give them more generic definitions (like we do with the non-qualifier portion of the purl).