I think a variance from the policy stated in mimetypes is quite possible, and the kind of information you provide, Terry, is a step in that direction.  We would need release manager approval, of course, since we are in Beta, but this is a small enough change I think it would fly, assuming the policy variance is approved.

For types_map, it's a doc bug.  It is indeed a tuple of dictionaries, the first being the limited, 'strict' set and the second normally including stuff from the "standard locations", which on windows includes the registry.

So, there is an argument in favor of adding the suffix map even if the types_map isn't updated for .svg, since the .svg mapping could come from one of the 'standard locations'.  I'd rather add both, though.