Arweave https://arweave.net/ is a cryptocurrency and network for permanent public data storage. It is not the first.
Sorry, that's the address of the team's official gateway. The website is https://arweave.org/ .
This is my local copy of ar/gateways.py from https://github.com/xloem/pyarweave which I am the sole maintainer of and engage occasionally for personal use (so the protocol is partly out of date and the code imperfect).
The list of mirrors from today is at the bottom. The metrics and statuses are likely different for you, but all the entries are included. They were made via ar.gateways.update_all() .
These are likely available online somewhere via the infrastructure at https://ar.io which the script uses but I am not up to date on. But now they are in your email too.
One the main purposes of an arweave gateway is to index subdata called "dataitems" which compose "bundles" on the arweave network. I started writing code for adding this directly to network peers at https://github.com/ArweaveTeam/arweave/compare/master...xloem:arweave:bundle... . My efforts stopped sadly 2 years ago when I was contacted by a network storage vendor in a way that influenced me more than I wanted. Things may have changed now, Arweave pleasant trends toward accessibility.
Note that github is not usually recommended in venues like this, it's quite literally the microsoft of codeforges.
Also, so you know, I found some duplicate certificates issued for official parts of this network some time ago. I linked them to the public evidence and it may have been addressed.