The "comments of the day" feature was removed from MediaWiki-extensions-Comments in b27c8bda334e94d0ca32e39c4167172e68d1963c in 2018 but BlogPage and LinkFilter for example weren't updated so setting $wgBlogPageDisplay['comments_of_day'] to true these days would trigger a PHP error due to the CommentsOfTheDay class being absent. That sucks.
Related: T174135: "Cannot use object of type Comment as array"
@ashley: Per emails from Sep18 and Oct20 and https://www.mediawiki.org/wiki/Bug_management/Assignee_cleanup , I am resetting the assignee of this task because there has not been progress lately (please correct me if I am wrong!). Resetting the assignee avoids the impression that somebody is already working on this task. It also allows others to potentially work towards fixing this task. Please claim this task again when you plan to work on it (via Add Action... → Assign / Claim in the dropdown menu) - it would be welcome. Thanks for your understanding!