Digital Inspiration: How Attachment Reminders work inside Gmail?

From Amit Agarwal, in case you were wondering: How Attachment Reminders work inside Gmail?. “If you haven’t seen this earlier, compose a new email in Gmail, add ‘I’ve attached the file’ in the body and hit send. Gmail will pop-up a warning saying – ‘it seems like you forgot to attach the file.’ How does the forgotten attachment detector work inside Gmail? I was looking at the source code of Gmail.com using Chrome Dev Tools and found an interesting snippet that bares it all.”