What triggers this PDF attachment box to be checked yes on Sch D?

[Just-Lisa-Now-]

This is down at the very bottom of the 109B worksheet, what triggers this box to be marked Yes?  I see the choice at the top of the page for the 8453 sending an attachment by paper, but what triggers this one?

[RollTide68 · Accepted solution]

Code M on the 8949 Adjustment Codes and an adjusted dollar amount.

[Just-Lisa-Now-]

thank you!