mobile-config-firefox/chrome/hide_urlbar_first_row.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/hide_urlbar_first_row.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Hides the first item in the urlbar dropdown if it is a "search with" or "visit" or "tab-to-search" item.  Does not hide "search in private window item", probably */

#urlbar[usertyping] .urlbarView-row:not([type]):first-child,
#urlbar[usertyping] .urlbarView-row[type="search"]:first-child,
.urlbarView-row[type="tabtosearch"] {
  display: none;
}