Intentional (Software) Qualities

I agree that qualities like "fast"/"performant" are intentional, and are thus prominently displayed in the project's readme, but are qualities like "maintainable" often found as a stated goal in readmes?

Or if the readme doesn't mention such qualities, can one assume that if it isn't deliberately fast etc. then it is likely to be maintainable because that quality hasn't been sacrificed for a different one?

I'm tempted to say no because not all developers necessarily have the experience to ensure their code base is easily maintainable, but assuming the developer(s) do have experience in writing clean code, is it then safe to assume it [is maintainable]?