There are lots of APIs defined on the Navigator object. For now, the common minimum API merely defines navigator.userAgent as part of the common APIs that WinterCG runtimes are interested in implementing.

However, it is being proposed to add more properties to Navigator in Node.js for usefulness (e.g. Navigator.hardwareConcurrency) and legacy compatibility (e.g. constant Navigator.appVersion version)

Current implementation status:

I believe the common APIs of Navigator should be extended to include attributes that were shipped in more than two runtimes. Also, if there are strong push-backs on adding the above APIs to the common minimum API, we should be wary of shipping them to reduce the gaps between the runtimes.