Form 8453 generates when the required attachments were not included as additional PDF files during e-File validation process. (Attaching PDF Documents to an E-file Return )

Upon e-File submission and acknowledgement of Accepted tax return, then mail the Form 8453 and required documentation Attachments where indicated on Form 

If you are using Paper File I presume attachments were literally physically attached and Form 8453 would not be needed

And then I found this Article specifically about Form 8453 Generating Form 8453