metamask-extension/ui/components/app/snaps/snap-delineator/index.scss

.snap-delineator {
  &__header {
    border-bottom-width: 1px;
    border-color: var(--color-border-default);
    border-style: solid;
    border-radius: 8px 8px 0 0;

    &__text {
      white-space: nowrap;
      text-overflow: ellipsis;
      overflow: hidden;
    }
  }
}