This is an umbrella for issues we think need to be resolved before entering the "ABI v1" stage - the point at which we wouldn't feel uncomfortable if people started porting to HPy or we proposed to upstream our ports in earnest. At this point, we consider HPy stable and complete enough to actually keep our promise of binary forward compatibility. That does not mean the abi cannot evolve, but that we feel comfortable that the ABI v1 we release at this point can be supported for many years