Semver is awesome. If the owner adheres to it, then it can be a very strong signal to the downstream users about whether they should be able to [probably] upgr

Semver is awesome. If the owner adheres to it, then it can be a very strong signal to the downstream users about whether they should be able to [probably] upgrade seamlessly vs possibly having to do some major rework. Also, if you see an adherent of semver bumping the major number all the time, you can choose whether you want to sign up for the churn on subsequent releases or not. Semver seems to encourage backwards compatibility. Not force, but encourage. There's a reason Microsoft and Intel worship backwards compatibility. Your downstream users love backwards compatibility.