logos-storage-module/docs/_static/custom.css

/* The "Tutorial" nav item links to the in-site doc-test report, not an external
   site, so drop the external-link arrow the theme adds to external_links. The
   arrow stays on genuinely external links (e.g. Logos). */
a.nav-external[href$="doctest/index.html"]::after {
  content: none;
}