Eclipse already provides much convenience for NLS support. IBM® WebSphere® Multichannel Bank Transformation Toolkit follows the same way to enable a widget to support NLS. Many description and label fields support NLS.
Bundle-Localization: plugin
desc_event_onclick = event triggered when the widget is clicked
For more information on how to enable NLS support, refer to the How to Internationalize your Eclipse Plug-In section in the Eclipse website.