As I understand the main goal is to make messages as much understandable as it can me. We need to find some balance between technical description and understand for non tech users. Lets discuss that.
I suggest that message:
Login with Superhero account at ${new Date().toUTCString()}
But as @davidyuk mentioned that message is not about sign. So maybe we can find something between technical description and understand for non tech users.
ref: #17