Bug 134740 [Wizards] PDE product wizard is not obvious to use.
see attached image. The wizard for creating a new product opens with a file name initialized to ".product" which is selected. Generally this would imply that this is a good default but if you start typing you will replace the text with something else that is also a good name. If you require an extension for a file you should add it yourself like the "Export Archive" wizard.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/dialogs/WizardNewFileCreationPage.java
*            the file handle to create a file resource with
	 * @param contents
	 *            the initial contents of the new file resource, or
	 *            <code>null</code> if none (equivalent to an empty stream)
	 * @param monitor
	 *            the progress monitor to show visual progress with
	 * @exception CoreException
	 *                if the operation fails
	 * @exception OperationCanceledException
	 *                if the operation is canceled
	 * 
	 * @deprecated As of 3.3, use or override {@link #createNewFile()} which
	 *             uses the undoable operation support. To supply customized
	 *             file content for a subclass, use
	 *             {@link #getInitialContents()}.
	 */
	protected void createFile(IFile fileHandle, InputStream contents,
			IProgressMonitor monitor) throws CoreException {
		if (contents == null) {
			contents = new ByteArrayInputStream(new byte[0]);
		}
		try {
			
			if (linkTargetPath != null) {
				fileHandle.createLink(linkTargetPath,
						IResource.ALLOW_MISSING_LOCAL, monitor);
			} else {
				IPath path = fileHandle.getFullPath();
				IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
				int numSegments = path.segmentCount();