What is the rationale behind apache's two remoteip directives; RemoteIPTrustedProxy vs remoteipinternalproxy

RemoteIPTrustedProxy does not accept internal addresses like 10.0.0.0/8.

remoteipinternalproxy accepts all addresses.

When should you use one or the other. The rationale is, as far as I can tell, not retrievable from Apache httpd's documentation.