Provide client information on how to register

I'm not exactly sure whether it's the right place here to propose, but I didn't find a better one...

Description:

Some Matrix servers use external authentication mechanisms, such as LDAP. In this case, Matrix clients are unable to perform a user registration the server does not seem to support this. I am looking for a way to work around this:

• the Matrix server should be able to communicate more precise information than that registration is impossible
• I thought of either a notice (e.g. a text telling where to register, or that registration is only available for foo bar baz)
• or a direct link to a registration page
• or of course the current information: Registration is impossible

I am unsure whether this is somehow possible at the moment.

No file, test, or entry point is named. Start by reviewing the Matrix registration specification and the current server response used when registration is unavailable, then compare the proposed notice, registration link, and existing failure information. Done means a decided protocol mechanism is specified for communicating external-registration details to clients.