Is there a convenient way to examine the source code for a Firefox extension before installing it?

(There is a [Chrome extension](https://chrome.google.com/webstore/detail/extension-gallery-and-web/bbamfloeabgknfklmgbpjcgofcokhpia) that offers this functionality, though I have not used it, and cannot say how well it works. At any rate, I am interested primarily in Firefox extensions.)