Works in Lynx, for some reason, as well as browsers that people actually use.
Relies on Dave Child’s TextStatistics for readability scores.
First, have Composer, npm, and PHP plus some common extensions.
On a Debian system (Jessie or better):
sudo apt-get install php-cli php-xml php-mbstring php-bcmath php-curl git clone https://gitlab.com/brennenpike/mw-category-readability.git cd mw-category-readability npm install composer install composer start
And then visit http://localhost:8080 in your browser of choice.