why we need processing the svg with sibling > descendant priority

[RedTrait]

Thanks to the author for contributing this library. While reading the source code, I found this comment. Why do we need to process the sibling nodes first?

let mut node_stack = tree
    .root()
    .children()
    .iter()
    // to make sure we are processing the svg with sibling > descendant priority we reverse it
    // and reverse the resulting descriptors before returning the final constructed svg
    .rev()
    .map(|node| NodeContext {
        node,
        transform: node.abs_transform(),
        is_text: false,
    })
    .collect::<VecDeque<_>>();