I haven't done much C++ in a few years but IIRC you can remove const as long as the "original" value isn't const. So `const_cast((*const Foo)foo)` is fine if foo is not const.

Isn’t the linker entitled to put a constant object in a read-only page of the binary if it doesn’t require a ctor at runtime?

Yes. That is why global static `const`s (with exceptions like if they have mutable fields) can't legally have their `const` casted away.