Function paste 

pub fn paste(
    indexed: &IndexedDocument<'_>,
    paste: Paste<'_>,
    fresh: &mut Allocator,
    builder: &mut CommitBuilder,
) -> Vec<Shape>

Inventory row “Paste”: insert a snapshot at the target scope, as a move or as a duplicate (Mode). Returns the roots — what the caller selects — leaving the nested structure that travelled inside them unnamed.