diff --git a/web/src/styles/app.css b/web/src/styles/app.css
index b9c3578..f3cbd4d 100644
--- a/web/src/styles/app.css
+++ b/web/src/styles/app.css
@@ -282,6 +282,11 @@ img { max-width: 100%; }
 .menu-item { display: flex; align-items: center; gap: 10px; width: 100%; padding: 8px 10px; border-radius: var(--radius-sm); text-align: left; color: var(--fg); white-space: nowrap; }
 .menu-item:hover, .menu-item.active { background: var(--bg-hover); }
 .menu-item:disabled { opacity: .5; cursor: default; }
+/* A menu entry that is a link still looks like a menu entry. The global rule
+   for `a` would otherwise colour and underline the one item that leaves the
+   app, which reads as a mistake rather than a distinction. */
+a.menu-item { text-decoration: none; color: var(--fg); cursor: pointer; }
+a.menu-item:hover { color: var(--fg); }
 .menu-item.danger { color: var(--danger); }
 .menu-item .menu-kbd { margin-left: auto; color: var(--fg-faint); font-size: .85em; }
 .menu-item svg { color: var(--fg-muted); flex: 0 0 auto; }
diff --git a/web/src/ui/popover.tsx b/web/src/ui/popover.tsx
index 518c77c..7e42dc2 100644
--- a/web/src/ui/popover.tsx
+++ b/web/src/ui/popover.tsx
@@ -120,14 +120,44 @@ export interface MenuItemProps {
   kbd?: string;
   active?: boolean;
   checked?: boolean;
+  /** Renders the item as a link. An external one gets a new tab. */
+  href?: string;
+  external?: boolean;
 }
 
-export function MenuItem({ icon, label, onClick, disabled, danger, kbd, active, checked }: MenuItemProps) {
-  return (
-    <button type="button" className={`menu-item ${danger ? "danger" : ""} ${active ? "active" : ""}`} onClick={onClick} disabled={disabled} role="menuitem">
+export function MenuItem({ icon, label, onClick, disabled, danger, kbd, active, checked, href, external }: MenuItemProps) {
+  const inner = (
+    <>
       {checked !== undefined ? <span style={{ width: 16, display: "inline-flex" }}>{checked ? "✓" : ""}</span> : icon}
       <span className="grow truncate">{label}</span>
       {kbd && <span className="menu-kbd">{kbd}</span>}
+    </>
+  );
+  const className = `menu-item ${danger ? "danger" : ""} ${active ? "active" : ""}`;
+  /*
+   * A real anchor when there is somewhere to go, rather than a button that
+   * calls window.open. The browser's own handling of a link comes with it --
+   * middle-click, a modifier-click, "open in new tab", the address on hover,
+   * copying it -- none of which a button offers however carefully it is
+   * scripted, and all of which someone expects from a menu entry that leaves
+   * the app.
+   */
+  if (href) {
+    return (
+      <a
+        className={className}
+        href={href}
+        role="menuitem"
+        onClick={onClick}
+        {...(external ? { target: "_blank", rel: "noopener noreferrer" } : {})}
+      >
+        {inner}
+      </a>
+    );
+  }
+  return (
+    <button type="button" className={className} onClick={onClick} disabled={disabled} role="menuitem">
+      {inner}
     </button>
   );
 }
diff --git a/web/src/views/AppShell.tsx b/web/src/views/AppShell.tsx
index a6421ad..e8a9198 100644
--- a/web/src/views/AppShell.tsx
+++ b/web/src/views/AppShell.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useState, type ReactNode } from "react";
 import { Link, useLocation } from "wouter";
-import { Calendar, ChevronsUpDown, FolderOpen, HelpCircle, LogOut, Mail, Menu as MenuIcon, Moon, PenSquare, Plus, RefreshCw, Settings, Sun, Upload, Users } from "lucide-react";
+import { BookOpen, Calendar, ChevronsUpDown, FolderOpen, HelpCircle, LogOut, Mail, Menu as MenuIcon, Moon, PenSquare, Plus, RefreshCw, Settings, Sun, Upload, Users } from "lucide-react";
 import { useSession } from "@/store/session";
 import { toggleTarget, useEffectiveTheme, useSettings } from "@/store/settings";
 import { useMail } from "@/store/mail";
@@ -101,6 +101,7 @@ export function AppShell({ children }: { children: ReactNode }) {
               </div>
             </div>
             <MenuSep />
+            <MenuItem icon={<BookOpen size={16} />} label="Documentation" href="https://docs.ihasmail.org" external />
             <MenuItem icon={<Settings size={16} />} label="Settings" onClick={() => navigate("/settings")} />
             <MenuItem icon={<RefreshCw size={16} />} label="Refresh" onClick={() => window.location.reload()} />
             <MenuItem icon={<LogOut size={16} />} label="Sign out" onClick={() => void logout()} />