helplogin-url is shown in a very prominent place by default and it should point to an existing page to avoid confusing users with links to nonexisting pages, similarly to bug 53862.
We have [[mw:Help:Logging in]], which given the author I assume ok and that can be made translatable when we are comfortable about the quality of its content (it had some "manual" translations on Meta). Linking it will help improve it, but it's already better than the default red link.
Version: 1.22.0
Severity: enhancement