mobile-config-firefox/chrome/hide_urlbar_first_row.css

/* Hides the first item in the urlbar dropdown if it is a "search with" or "visit" 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 {
  display: none;
}