select2/docs/_sass/_anchorjs.scss

// AnchorJS Styles

.anchorjs-link {
  color: inherit;
  transition: all .16s linear;
  text-decoration: none;

  &:link,
  &:visited {
    text-decoration: none;
    color: inherit;
  }

  @media (max-width: 480px) {
    display: none;
  }
}

*:hover > .anchorjs-link {
  opacity: .5;
  margin-left: -0.9em !important;
}

*:hover > .anchorjs-link:hover,
.anchorjs-link:focus {
  opacity: 1;
}