Why is usage of the downloadURL & updateURL keys called unusual and how do they work?

Use of those keys is discouraged mainly by Greasemonkey’s lead developer. Most others, including the Tampermonkey team feel no need for such a warning. Also note that those directives are not always required for auto-updates to work. Some reasons why he would say that it was unusual and that “most” scripts should omit it: In … Read more