Maintenance fork of the Enjoy Reading addon by jblanche. This, unlike the upstream, works with current Firefox versions.
XPI download (for installing in Firefox): http://pub.lrem.net/2013/09/enjoy-reading-2.xpi
The upstream: https://addons.mozilla.org/en-us/firefox/addon/enjoy-reading/
The only one that got through before AMO took down the add-on:
I've had bad eyes my whole life and reading various sites can be tricky for me. I think I've tried every other spawn-of-Readability addon available, but this one is the absolute best. Thank you so much for keeping it alive! It is something I use easily a dozen times every day and it improves the quality of my online life more than I can even express with words.
This is not in AMO for good reasons. Seems that it is impossible right now to submit readability-based add-on. The reply is broken down in the issues page. None of the problems have been introduced in this fork.