chromium/chrome/browser/resources/side_panel/shared/sp_list_item_badge.html

<style>
  :host {
    height: 20px;
    align-items: center;
    background: var(--color-side-panel-badge-background);
    border-radius: 100px;
    box-sizing: border-box;
    color: var(--color-side-panel-badge-foreground);
    display: inline-flex;
    flex-direction: row;
    font-size: 11px;
    gap: 0;
    line-height: normal;
    padding: 4px 8px 4px 6px;
  }

  :host([updated]) {
    background: var(--color-side-panel-badge-background-updated);
    color: var(--color-side-panel-badge-foreground-updated);
    font-weight: 400;
  }

  ::slotted(iron-icon) {
    color: inherit;
    height: 12px;
    width: 12px;
    padding-inline-end: 4px;
  }

  ::slotted([slot=previous-badge]) {
    color: var(--color-side-panel-badge-foreground);
    font-weight: 400;
    text-decoration: line-through;
    padding-inline-start: 2px;
  }
</style>
<slot></slot>
<slot name="previous-badge"></slot>