stable-diffusion-webui/html/extra-networks-pane-tree.html

    <div class="extra-network-pane-content-tree resize-handle-row">
        <div id='{tabname}_{extra_networks_tabname}_tree' class='extra-network-tree' style='flex-basis: {extra_networks_tree_view_default_width}px'>
            {tree_html}
        </div>
        <div id='{tabname}_{extra_networks_tabname}_cards' class='extra-network-cards' style='flex-grow: 1;'>
            {items_html}
        </div>
    </div>