public static boolean isIconKey(String key) {
		return StringUtils.startsWithAny(key, ICON_ID_PREFIX, EXTERNAL_PREFIX,
			EXTERNAL_LAF_ID_PREFIX);
	}
Returns true if the given key string is a valid external key for an icon value
@param key the key string to test
@return true if the given key string is a valid external key for an icon value
Ghidra/Framework/Gui/src/main/java/generic/theme/IconValue.java