For example, I can change my username here on this instance. So long as my email id remains the same, my account is operable.
But GitHub doesn’t allow me to change my username. On top of that, GitHub forces an identifier on you when you create your username.
Being open source has nothing to do with it, it’a more about how they implement the username system. I don’t think Lemmy allows you to change the identifier, only how it’s displayed. Just checked GitHub and they allow you to change your ID as well as your display name.
I applied this feature. But they’re modifying the username that l propose.