Distributing code or documentation is subject to legal requirements, and CRAN operates in many jurisdictions.
One of the aims of these policies is to ensure that the distributors meet their legal obligations of diligence without excessive work.
Your web accessibility policy may be standalone or integrated into other policies, such as non-discrimination or equal opportunity policies.
Ideally web accessibility should also be reflected in related documents, such as brand guidelines, coding standards, and project management frameworks.
Think of gates and policies like routes and controllers.