You’re like the third person to post about this specific issue recently, mind sharing what guide you’re using so I can bug whoever maintains it to update it a touch?
Long story short:
You’re reading an old guide, use the bin or json files in place of the eml file and everything will work fine
This is a pretty common default key, it just means the card probably doesn’t have anything super fancy on it (Unless there are keys you aren’t finding) and might just use UID to authenticate with whatever system it uses. Or maybe it just uses default keys, who knows?