@Nonnull
	default String getExtension() {
		if (getOriginalResource() != null) {
			return Util.extension(getOriginalResource());
		} else {
			return "";
		}
	}
Retrieves the file extension of the resource represented by this reference.

@return the file extension of the resource, or an empty string if no
        extension is found
src/main/java/dev/jbang/source/ResourceRef.java