How does firefox know when an update is available for an extension (plugin)

Question

I am in the process of creating my first firefox extension and am starting to think about deployment.

There is a nice discussion about creating an template here and signing the extension here

But later down the road ... how does firefox know that an extension has been updated?

Answer 1

From developer.mozilla.org :

Applications will periodically check for updates to installed add-ons by retrieving the updateURL. The information returned can be used to notify the user of an updated version to the add-on as well as inform the application of new application versions that the add-on is compatible with.

More details about updateURL.