SemVer works great for libraries, but it falls apart for actual software IMO. How would you define a "breaking change" in a software ? Would it be a complete redesign ? Or maybe a feature removal (Does that ever happen ?)

Versions are supposed to convey meaning over how much has changed to the app between two versions. iTerm got soooooo many new features in this new version, anything smaller than a major bump would feel out of place.

I do agree the actual version should be v3.0.0-beta1 tho ^^.