by the way i have an idea which will easily allow to expose internals of xint to satisfy demands of some reviewers say, we have a set of different backends lets call the current backend "sign_magnitude_beta" then everything can be exposed in the namespace hierarchy like this: xint::backend::sign_magnitude_beta::some_entity or xint::sign_magnitude_beta::backend::some_entity then when chad desides to switch to a differnent (e.g. faster) backend which may be called "sign_magnitude_v1" we got xint::backend::sign_magnitude_v1 _along_ with that "sign_magnitude_beta" on which some user code may be dependent this way the chance that xint lib breaks compatibility is almost zero and simultaneously it doesn't limit the development in any way eventually in some years the old (expired) backends may be removed -- Pavel P.S. if you notice a grammar mistake or weird phrasing in my message please point it out