Firefox’s free VPN will offer 50 gigabytes of monthly data, which is pretty generous for a browser-based VPN. A Mozilla account is required to make use of it, which isn’t a hardship (they’re free), but is a point of friction some may wish to know upfront.
disregard what I said on my other comment. I believe it to be correct, but despite the post title this is not a VPN, but a proxy, as the article says, that needs to decrypt the HTTPS traffic.
weird choice to be honest.