How to download Firefox extensions from addons.mozilla.org without installing them?

Pages at the https://addons.mozilla.org/en-US/firefox site often feature buttons that say "Add to Firefox".

Clicking on such a button causes a Firefox extension to be downloaded and installed.

I am looking for a convenient way to limit this action to the download step only, so that in the end I am left with the downloaded *.xpi file in my disk.

Thanks!

P.S. The following approach is not only inconvenient: it doesn't work!.

1. Inspect the HTML for the button, and extract a URL like

   https://addons.mozilla.org/firefox/downloads/latest/1234/addon-1234-latest.xpi?src=search

   give or take the stuff after .xpi.

2. at the command-line prompt, download this URL with wget or curl.

This download attempt just hangs. (Even if it didn't, I'd like to find a less cumbersome approach.)

In Firefox, right-click on the download button and select "save link as" has always worked for me.

Go to the add-on you want to install and just right click on the +Add to Firefox button and select save link as. After downloading the file just go to File>Open File and just select the extension you have downloaded work like a charm for me.