"Send to Kindle" by Amazon add-on?

I thought Firefox had an extension for Send to Kindle that was produced by Amazon, but I can’t find it. Is it still around?

Push to Kindle isn’t working for me anymore - it says sent, but never arrives.


I do not think they have been developed by Amazon, but these might help:


If an add-on does not work, best to reach out to the developer directly using the support link on the page that you have downloaded the add-on from.