It is incomplete: <a href="https:&#x2F;&#x2F;github.com&#x2F;apple&#x2F;swift-corelibs-foundation&#x2F;search?utf8=%E2%9C%93&amp;q=NSUnimplemented%28%29" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;apple&#x2F;swift-corelibs-foundation&#x2F;search?ut...</a>