Some very large servers are eligible for what Discord calls "discovery". This makes their data visible without joining the server. You can find a list of those on Discord's site here: https://discord.com/servers
Suggestion: a bot for smaller servers that do want to be archived like a public forum. Their admins could install the bot themselves and perhaps specify what channels they want archived.
This is something I have already completed but have not finished bug testing. The bot also includes functionality to recover any server in case it was nuked/wiped and Searchcord has a backup of it. It uses webhooks to resend the messages so you have an approximation of what the channels used to be.
