Should an indicator of size be a data attribute in the optional core schema? Or is this an extension?

[shuyag]

In a use case conversation, we brought up how size of a production facility is helpful to know in terms of due diligence reporting and/or to estimate how well resourced a location is.

Is it helpful to add in, as an optional data field in the core schema, some indicator of size like square footage of production facility or number of workers? OR is does this make for a great extension/use case specifically for size?