Jörg Jenderek wrote:
normally files compressed with gzip have filename extension "gz" and mime type "application/gzip". When compressing tar archives often these get file name extension "tgz". The VirtualBox Extension Packs seems to be also gzipped tar archives. But these get their own file name extension "vbox-extpack" and mime type "application/x-virtualbox-vbox-extpack" at least for VirtualBox 6.0.4 on Windows systems. I am trying to refine definitions for file identifying utilies TrID ( http://mark0.net/soft-trid-e.html) and file ( ftp://ftp.astron.com/pub/file ). Such utilities simply use some characteristics byte patterns to identify file types. As far as i can see, it is not possible at the moment for both utilities to distinguish gzipped tar files from VirtualBox extension packages. If the gzipped file would contain a comment field or other extra field, it would be possible to distinguish such different file types.
OK, I see; you're trying to improve TrID etc., since they're not smart enough to uncompress the file to figure out its file type. However, can't these utilities use file name extensions? If so, I suggest using some extension like ".vep" for VirtualBox Extension Packs, as that won't require changing gzip and other programs that accept and consume gzip files.
