From Jeff's answer to the deleted question* linked to from the question you link to:

Your name is inferred from your openid until you specify a display name. You have no display name specified.

 

Thus your inferred username is ...

 

~quack

 

... because it's based on your openid URL. It's not an actual, valid display name.

If you check unutbu's page there's no name specified.

* visible only to 10K+ meta users.

From Jeff's answer to the deleted question* linked to from the question you link to:

Your name is inferred from your openid until you specify a display name. You have no display name specified.

Thus your inferred username is ...

~quack

... because it's based on your openid URL. It's not an actual, valid display name.

If you check unutbu's page there's no name specified.

* visible only to 10K+ meta users.

From Jeff's answer to the deleted question* linked to from the question you link to:

Your name is inferred from your openid until you specify a display name. You have no display name specified.

Thus your inferred username is ...

~quack

... because it's based on your openid URL. It's not an actual, valid display name.

If you check unutbu's page there's no name specified.

* visible only to 10K+ meta users.

From Jeff's answer to the deleted question* linked to from the question you link to:

Your name is inferred from your openid until you specify a display name. You have no display name specified.

Thus your inferred username is ...

~quack

... because it's based on your openid URL. It's not an actual, valid display name.

If you check unutbu's page there's no name specified.

* visible only to 10K+ meta users.