[Resending, as it looks like my original message didn't make it.] Chris, The latest version of the registration is an improvement. However based on our earlier private discussion I've decided to ask for some additional feedback regarding associating both XML and GZIPed version of the same format with a single media type. Below are some comments received from email experts during YAM WG meeting in Maastricht: MIME experts think that using +xml for gzipped material is a really bad idea, and that having two extensions for one MIME type, with different semantics, and with a dependency on transfer-encoding, is a bad idea. This looks like MIME type sniffing and MIME media types were explicitly designed to avoid this. The cleanest way to fix this (without having a long debate about what is correct and what is not according to MIME spec) is to have 2 separate MIME type registrations (one for XML and one for gzipped version), each using own file extension. Additionally Mark Nottingham pointed out that the following text is not correct: SVG documents may be transmitted in compressed form using gzip compression. For systems which employ MIME-like mechanisms, such as HTTP, this is indicated by the Content-Transfer-Encoding header; for systems which do not, such as direct filesystem access, this is indicated by the filename extension and by the Macintosh File Type Codes. because Content-Transfer-Encoding header field is not used in HTTP.