Function cut 

pub fn cut(
    indexed: &IndexedDocument<'_>,
    targets: &[Target],
    from: DocumentNonce,
    builder: &mut CommitBuilder,
) -> Clipboard

Cut: the snapshot and the cascade delete in one commit.

What the delete declines — a pin whose owner froze its interface — the copy declines too, which is why this walks the delete’s own closure rather than copy’s. A cut that left something on the clipboard it also left in the document would make the next paste read a mix of held and departed sources, and duplicate where the user asked for a move.