--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -6854,16 +6854,20 @@ var gIdentityHandler = {
   get _permissionEmptyHint() {
     delete this._permissionEmptyHint;
     return this._permissionEmptyHint = document.getElementById("identity-popup-permission-empty-hint");
   },
   get _permissionReloadHint() {
     delete this._permissionReloadHint;
     return this._permissionReloadHint = document.getElementById("identity-popup-permission-reload-hint");
   },
+  get _popupExpander() {
+    delete this._popupExpander;
+    return this._popupExpander = document.getElementById("identity-popup-security-expander");
+  },
   get _permissionAnchors() {
     delete this._permissionAnchors;
     let permissionAnchors = {};
     for (let anchor of document.getElementById("blocked-permissions-container").children) {
       permissionAnchors[anchor.getAttribute("data-permission-id")] = anchor;
     }
     return this._permissionAnchors = permissionAnchors;
   },
@@ -6875,20 +6879,28 @@ var gIdentityHandler = {
   handleMoreInfoClick(event) {
     displaySecurityInfo();
     event.stopPropagation();
     this._identityPopup.hidePopup();
   },
 
   toggleSubView(name, anchor) {
     let view = this._identityPopupMultiView;
+    let id = `identity-popup-${name}View`;
+    let subView = document.getElementById(id);
+
+    // Listen for the subview showing or hiding to change
+    // the tooltip on the expander button.
+    subView.addEventListener("ViewShowing", this);
+    subView.addEventListener("ViewHiding", this);
+
     if (view.showingSubView) {
       view.showMainView();
     } else {
-      view.showSubView(`identity-popup-${name}View`, anchor);
+      view.showSubView(id, anchor);
     }
 
     // If an element is focused that's not the anchor, clear the focus.
     // Elements of hidden views have -moz-user-focus:ignore but setting that
     // per CSS selector doesn't blur a focused element in those hidden views.
     if (Services.focus.focusedElement != anchor) {
       Services.focus.clearFocus(window);
     }
@@ -7187,16 +7199,19 @@ var gIdentityHandler = {
   refreshIdentityPopup() {
     // Update "Learn More" for Mixed Content Blocking and Insecure Login Forms.
     let baseURL = Services.urlFormatter.formatURLPref("app.support.baseURL");
     this._identityPopupMixedContentLearnMore
         .setAttribute("href", baseURL + "mixed-content");
     this._identityPopupInsecureLoginFormsLearnMore
         .setAttribute("href", baseURL + "insecure-password");
 
+    // The expander switches its tooltip when toggled, change it to the default.
+    this._popupExpander.tooltipText = gNavigatorBundle.getString("identity.showDetails.tooltip");
+
     // Determine connection security information.
     let connection = "not-secure";
     if (this._isSecureInternalUI) {
       connection = "chrome";
     } else if (this._isURILoadedFromFile) {
       connection = "file";
     } else if (this._isEV) {
       connection = "secure-ev";
@@ -7396,16 +7411,26 @@ var gIdentityHandler = {
   onPopupHidden(event) {
     if (event.target == this._identityPopup) {
       window.removeEventListener("focus", this, true);
       this._identityBox.removeAttribute("open");
     }
   },
 
   handleEvent(event) {
+    // If the subview is shown or hidden, change the tooltip on the expander button.
+    if (event.type == "ViewShowing") {
+      this._popupExpander.tooltipText = gNavigatorBundle.getString("identity.hideDetails.tooltip");
+      return;
+    }
+    if (event.type == "ViewHiding") {
+      this._popupExpander.tooltipText = gNavigatorBundle.getString("identity.showDetails.tooltip");
+      return;
+    }
+
     let elem = document.activeElement;
     let position = elem.compareDocumentPosition(this._identityPopup);
 
     if (!(position & (Node.DOCUMENT_POSITION_CONTAINS |
                       Node.DOCUMENT_POSITION_CONTAINED_BY)) &&
         !this._identityPopup.hasAttribute("noautohide")) {
       // Hide the panel when focusing an element that is
       // neither an ancestor nor descendant unless the panel has

--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -438,16 +438,18 @@ offlineApps.usage=This website (%S) is n
 offlineApps.manageUsage=Show settings
 offlineApps.manageUsageAccessKey=S
 
 identity.identified.verifier=Verified by: %S
 identity.identified.verified_by_you=You have added a security exception for this site.
 identity.identified.state_and_country=%S, %S
 
 identity.icon.tooltip=Show site information
+identity.showDetails.tooltip=Show connection details
+identity.hideDetails.tooltip=Hide connection details
 
 trackingProtection.intro.title=How Tracking Protection works
 # LOCALIZATION NOTE (trackingProtection.intro.description2):
 # %S is brandShortName. This string should match the one from Step 1 of the tour
 # when it starts from the button shown when a new private window is opened.
 trackingProtection.intro.description2=When you see the shield, %S is blocking some parts of the page that could track your browsing activity.
 # LOCALIZATION NOTE (trackingProtection.intro.step1of3): Indicates that the intro panel is step one of three in a tour.
 trackingProtection.intro.step1of3=1 of 3