@kasperb So, verdict is as follows:
Reddit no longer allows anonymous JSON fetches. This is now officially dead.
I can maybe make it work for users who have OAuth creds, but I would need to know if it would be worth the while me making those changes, i.e. are there current users of the module who have OAuth creds or not? If not then this module is unfortunately “as good as dead”.
They, Reddit, have moved onto Devvit which is hosted inside Reddit’s platform and handles authentication for apps built on the platform. Not used for external apps.
If there are any users who have OAuth creds, let me know and I will update the module, else I will have to shelve this one.