Old icons for new tab and closed tabs. Vivaldi Browser.

/* old newtab icon */
#tabs-container > div.resize > div > div > div > button > span > svg path {
    d:path('M9,6C7.3,6,6,7.3,6,9v10c0,1.7,1.3,3,3,3h10c1.7,0,3-1.3,3-3V9c0-1.7-1.3-3-3-3H9z M9,15h4v4h2v-4h4v-2h-4V9h-2v4H9V15z');
}

/* old closed tabs icon */
#tabs-container > div.toolbar.toolbar-tabbar.sync-and-trash-container > div > button > span > svg path {
    d:path('M16.5 8c-.3 0-.5-.2-.5-.5v-1c0-.3-.2-.5-.5-.5h-4c-.3 0-.5.2-.5.5v1c0 .3-.2.5-.5.5H8c-.6 0-1 .4-1 1s.4 1 1 1h11c.6 0 1-.4 1-1s-.4-1-1-1h-2.5zM18 11c.6 0 1 .4 1 1v8c0 1.1-.9 2-2 2h-7c-1.1 0-2-.9-2-2v-8.1c.1-.5.6-.9 1.1-.9.5.1.8.4.9.9V19c0 .6.4 1 1 1h5c.6 0 1-.4 1-1v-7.1c.1-.5.5-.9 1-.9z');
    stroke: none;
    stroke-width: 1;
    fill: currentColor;
}

#tabs-container > div.toolbar.toolbar-tabbar.sync-and-trash-container > div > button > span > svg > path:nth-child(1) {
    d:path('M11,11v8h1v-8H11z M13,11v8h1v-8H13z M15,19v-8h1v8H15z');
    opacity: 0.65;
}

#tabs-container > div.toolbar.toolbar-tabbar.sync-and-trash-container > div > button > span > svg > line:nth-child(3) {
    display: none;
}

#tabs-container > div.toolbar.toolbar-tabbar.sync-and-trash-container > div > button > span > svg > line:nth-child(4) {
    display: none;
}