Is DomainType actually necessary?

[KathiSchleidt]

Seems like a helper attribute, the actual information is available in the coverage domain. In modern programming, I'd assume that developers interrogate the domain, understand the shape of the coverage.

The currently available permutations are already limiting (see #198 ), if we add more domain options (multiple times, enum axes), this set of permutations will explode.

Could we at least make provision of DomainType optional?

[jonblower]

domainType is already an optional (albeit recommended) attribute. It makes client development easier and also helps with schema validation. If people want to define new domain types they can propose new ones, or just omit domainType altogether if their use case doesn't fit any of the existing ones.