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
*         <code>null</code> if no path is known
	 */
	public IPath getContainerFullPath() {
		return resourceGroup.getContainerFullPath();
	}
	/**
	 * Returns the current file name as entered by the user, or its anticipated
	 * initial value.
	 * 
	 * @return the file name, its anticipated initial value, or
	 *         <code>null</code> if no file name is known
	 */
	public String getFileName() {
		if (resourceGroup == null) {
			return initialFileName;
		}
		return resourceGroup.getResource();
	}
	/**
	 * Returns a stream containing the initial contents to be given to new file
	 * resource instances. <b>Subclasses</b> may wish to override. This default
	 * implementation provides no initial contents.
	 * 
	 * @return initial contents to be given to new file resource instances
	 */
	protected InputStream getInitialContents() {
		return null;
	}
	/**
	 * Returns the label to display in the file name specification visual