@Gozala Agreed - if there's no install.rdf and no package.json, it's not a valid extension. The presence of a bootstrap.js shouldn't factor into detecting what type of extension it is.

However, if we first check for install.rdf, and then package.json, developers won't be able to write backwards compatible extensions. Which is fine, but something to note. If we checked package.json first, developers could write extensions that used the new method as well as include the right stuff for it to be backwards compatible for versions of the application that only support install.rdf/bootstrap.js.