[Mtinie]

I believe you are misremembering the details. There is a free account option, but code signing isn't available.

https://developer.apple.com/support/compare-memberships/

What's not clear to me, however, is if the educational option allows for free developer-level memberships.

[SyneRyder]

Thank you! I'd confused it with recent changes to the iOS program allowing people to self-sign so they can test on their own iOS devices.

It looks like Educational memberships are Sign-In With Apple ID only, which doesn't provide a Developer ID (which is required for code signing, as far as I can tell).