In Firefox (Windows, latest version 50+), is there a way to configure it so that specific sites' pages are automatically opened in Reader View?
Firefox's Reader View help page didn't yield any results.
Please note: I am asking for an automated switch to Reader View (not manual like this question); and the question assumes that the given site fully supports Reader View, so every page already has the view icon available).
I think I have a reasonable answer for you, but it's a bit buggy.
Via the Readability based Reader View add-on I can get an entire site to switch to Reader mode.
Firstly, although this isn't the official FireFox Reader View it is using the underlying Readability library:
This extension enhances the readability of web pages by removing clutter. It uses Mozilla's Readability library to provide a similar experience to the one you get when using Firefox.
-- FAQ
Once you've installed it you can actually get an entire site to switch to Reader View via the options.
There is an 'Automatic Switch' section where you can specify
a comma-separated list of hostnames or regular expressions to automatically switch to the reader view
For example I chose mathshistory.st-andrews.ac.uk (note a regular URL https://mathshistory.st-andrews.ac.uk doesn't work).
On top of that I ticked the 'Link Opening' checkbox that opens the links in the Reader View also in the Reader View. This effectively means I can stay in Reader View for the entire site.
It has a bug/feature where if you use Alt+Backspace it switches back to normal view.
Since you want just a particular page you can use something like:
mathshistory.st-andrews.ac.uk/Biographies/Abu_Kamil/
in the options.
