hoppscotch/packages/hoppscotch-app/assets/icons/sidebar.svg

<svg
  xmlns="http://www.w3.org/2000/svg"
  width="24"
  height="24"
  viewBox="0 0 24 24"
  fill="none"
  stroke="currentColor"
  stroke-width="2"
  stroke-linecap="round"
  stroke-linejoin="round"
>
  <rect x="3" y="3" width="18" height="18" rx="2" ry="2" />
  <line x1="9" y1="3" x2="9" y2="21" />
</svg>