Background

Currently, there are multiple API calls when loading the special page:

There is an API call to get the list of pages in the reading list http://enwiki.mediawiki.mwdd.localhost:8080/w/api.php?action=query&format=json&list=readinglistentries&rlelists=4&rlesort=updated&rledir=descending&rlelimit=12&formatversion=2
Then calls for page metadata https://en.wikipedia.beta.wmcloud.org/w/api.php?action=query&format=json&origin=*&prop=info%7Cdescription%7Cpageimages&titles=Capitol_View%2C_Atlanta%7CCanton_of_Rozoy-sur-Serre%7CCaptain_Feathersword%7CChildren_of_Henry_VIII%7CWales%7CLlanfairpwllgwyngyll%7CBrown_bear%7CQueens%7CNew_York_City%7CPolar_bear&redirects=true&inprop=url&piprop=thumbnail&pilicense=any&pithumbsize=200&pilimit=10&formatversion=2 (possibly many if the reading list has a lot of pages)

There is a Spike associated with this work that includes an ADR and 2 POC patches.