[[P3045R10]](https://wg21.link/p3045r10) supplies the type system. It does not supply the SI. A user who includes the framework gets `quantity`, `unit`, `quantity_spec`, `prefix` — but no `metre`, no `kilogram`, no `second`. The framework is deliberately content-agnostic: it supports arbitrary systems of quantities and units. Shipping the framework without SI content would be like shipping `<algorithm>` without `<vector>` — or the coroutine framework without `std::task`.