grafana/public/sass/components/_infobox.scss

.grafana-info-box:before {
  content: "\f05a";
  font-family:'FontAwesome';
  position: absolute;
  top: -8px;
  left: -8px;
  font-size: 20px;
  color: $blue;
}

.grafana-info-box {
  position: relative;
  padding: 5px 15px;
  background-color: $tight-form-bg;
  border: 1px solid $tight-form-border;
  h5 {
    margin-top: 5px;
  }
}