TL;DR: Prepend “about:reader?url=” to any website URL to force reader view in Firefox
I’m in love with Firefox’ reader view. It not only removes ads, nag-screens, subscription prompts and other clutter from articles but it’s typographical choices often are better than the (well-intended) choices of the author. I also value the consistent look and feel the reader view adds across a wide spectrum of web sites.
Firefox shows the reader view icon only on some websites, for reasons I can only speculate about. A post by addon author “Firefox user 12286934” notes that prepending about:reader?url= to a website’s URL enables reader view – and it works!
Tested with FF 74.0
George's Techblog 
Alternately, you can also set “reader.parse-on-load.force-enabled” to “true” in Firefox’s about.config. It will display the “Toggle reader view” icon in the address bar.
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With 75.0 that setting exists but doesn’t seem to have any effect
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Ah! I got it working on 68.7.0 ESR version. Strange that it’s broken on the mainline.
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Thank you! What an awesome tip, exactly what I needed.
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