→Why doesn't GRAMPS just use a .gz extension?
GRAMPS uses the [http://freedesktop.org/wiki/Software/shared-mime-info Shared Mime System] defined by [http://freedesktop.org Free Desktop] project, and used by all major desktops, including KDE and GNOME. GRAMPS relies on the MIME type identified by the Shared Mime System to determine the file type of the file.
The Share Mime System allows you to identify a file's type by either using a file extension or by looking at the contents of a small section of the file. The first problem is, usually the filename or extension pattern has the higher priority compared to the contents: if the file is named <code>something.jpg</code> then it is likely to be JPEG image, not text.
The second problem is, if we looked at the contents, we would not be able to tell the difference between a gzip'd GRAMPS XML file or any other gzip'd file. If we looked at uncompressed data, we would not be able to tell the difference between a GRAMPS XML file and other XML files. For these reasons, we must rely on the <code> .gramps</code> extension.
GRAMPS is not unique in this problem. For example, the OpenDocument format used by OpenOffice, KWord and AbiWord is actually a collection of files in a <tt>zip</tt> archive. If you run <tt>unzip</tt> on a OpenDocument file, you will see something like: