The macro enum type parameter currently does not support the internationalisation of its values.

macro-browser-fields.js:331-333

...
$(param.enumValues).each(function() {
    input.append(AJS.$("<option/>").attr("value", this).html("" + this));
});
...

The data is coming from a JSON response of /plugins/macrobrowser/browse-macros.action, see macro-browser.js (data.macros):1060-1063

...
url: AJS.params.contextPath + "/plugins/macrobrowser/browse-macros.action",
success: function(data) {
    t.initData = data;
    t.loadModel(data.macros);
...

and the corresponding server-side action, com.atlassian.confluence.macro.browser.actions.BrowseMacrosAction leading to com.atlassian.confluence.plugin.descriptor.MacroMetadataParser.parseParameter(String, String, Element) and com.atlassian.confluence.macro.browser.beans.MacroParameter. For the i18n to achieve there, the enumValues field should be changed from a List<String> to a Map<String, Message> where String is a specific value and Message is the convention established for resolving the translation. See also e.g. com.atlassian.confluence.macro.browser.beans.MacroParameter.getDescription()):173

return Message.getInstance(pluginKey + "." + macroName + ".param." + name + ".desc");

Suggested convention would be

pluginKey + "." + macroName + ".param." + name + ".value." + value

where value is the key of the enumValues map. The implementation of the map should be a java.util.LinkedHashMap, so that the order from the XML is maintained.