Based on the code, Zend_Mime is strictly limited to mail-related functionality. A quick grep also shows that it is only used in Zend_Mail and Zend_Mail_Part. Why is this a top-level component?
When I think of Zend_Mime, I think of Mime Magic functionality: parsing a magic file to determine the content type of a file, like 'application/x-tar'. This actually threw me off today, because I looked into Zend_Mime expecting functionality like this. PHP's mime_content_type() is deprecated in favor of Fileinfo, but Fileinfo is a PECL extension--a rather irritating one to install on Linux, incidentally. Portability would be easier with a native PHP magic.mime parser, but that can't happen while Zend_Mime occupies its current place. Thoughts? -Matt