This error popped up for me in Firefox:
TypeError: ServiceWorker script at <a href="<a href=" https:="" html-classic.itch.zone="" html="" 17642705="" "="">https://html-classic.itch.zone/html/17642705/</a>ServiceWorker.js" class="redactor-linkify-object">https://html-classic.itch.zone/html/17642705/ServiceWorker.js for scope https://html-classic.itch.zone/html/17642705/ encountered an error during installation.