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
/**
	 * Sets the value of this page's file name field, or stores it for future
	 * use if this page's controls do not exist yet.
	 * 
	 * @param value
	 *            new file name
	 */
	public void setFileName(String value) {
		if (resourceGroup == null) {
			initialFileName = value;
		} else {
			resourceGroup.setResource(value);
		}
	}
	/**
	 * Checks whether the linked resource target is valid. Sets the error
	 * message accordingly and returns the status.
	 * 
	 * @return IStatus validation result from the CreateLinkedResourceGroup
	 */
	protected IStatus validateLinkedResource() {
		IPath containerPath = resourceGroup.getContainerFullPath();
		IPath newFilePath = containerPath.append(resourceGroup.getResource());
		IFile newFileHandle = createFileHandle(newFilePath);
		IStatus status = linkedResourceGroup
				.validateLinkLocation(newFileHandle);
		if (status.getSeverity() == IStatus.ERROR) {
			if (firstLinkCheck) {
				setMessage(status.getMessage());
			} else {