actually called it 'biometrics'. They took my
picture and signature. Today, I went the local office
for infopass appointment. After waiting for 4 hours
there, when it came to my turn, the officer said that
I did not need to come since I already got my green card. He was actually confused why I got the card before I did passport stamp. Anyway, he did nothing,
no passport stamp. He did not even want to take away
my I-94.