--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -485,23 +485,16 @@ pref("browser.tabs.drawInTitlebar", fals
 #else
 pref("browser.tabs.drawInTitlebar", true);
 #endif
 
 // Offer additional drag space to the user. The drag space
 // will only be shown if browser.tabs.drawInTitlebar is true.
 pref("browser.tabs.extraDragSpace", false);
 
-// 0 - Disable the tabbar session restore button.
-// 1 - Enable the tabbar session restore button.
-// 2 - Control group. The tabbar session restore button is disabled,
-// but we will record data on other session restore usage.
-// To be enabled with shield.
-pref("browser.tabs.restorebutton", 0);
-
 // When tabs opened by links in other tabs via a combination of
 // browser.link.open_newwindow being set to 3 and target="_blank" etc are
 // closed:
 // true   return to the tab that opened this tab (its owner)
 // false  return to the adjacent tab (old default)
 pref("browser.tabs.selectOwnerOnClose", true);
 
 pref("browser.tabs.showAudioPlayingIcon", true);

--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -8709,68 +8709,30 @@ function switchToTabHavingURI(aURI, aOpe
       openUILinkIn(aURI.spec, "tab", aOpenParams);
   }
 
   return false;
 }
 
 var RestoreLastSessionObserver = {
   init() {
-    let browser_tabs_restorebutton_pref = Services.prefs.getIntPref("browser.tabs.restorebutton");
-    Services.telemetry.scalarSet("browser.session.restore.browser_tabs_restorebutton", browser_tabs_restorebutton_pref);
-    Services.telemetry.scalarSet("browser.session.restore.browser_startup_page", Services.prefs.getIntPref("browser.startup.page"));
     if (SessionStore.canRestoreLastSession &&
         !PrivateBrowsingUtils.isWindowPrivate(window)) {
-      if (browser_tabs_restorebutton_pref == 1) {
-        let {restoreTabsButton, restoreTabsButtonWrapperWidth} = gBrowser.tabContainer;
-        let restoreTabsButtonWrapper = restoreTabsButton.parentNode;
-        restoreTabsButtonWrapper.setAttribute("session-exists", "true");
-        gBrowser.tabContainer.updateSessionRestoreVisibility();
-        restoreTabsButton.style.maxWidth = `${restoreTabsButtonWrapperWidth}px`;
-        gBrowser.tabContainer.addEventListener("TabOpen", this);
-        Services.telemetry.scalarSet("browser.session.restore.tabbar_restore_available", true);
-        restoreTabsButton.addEventListener("click", () => {
-          Services.telemetry.scalarSet("browser.session.restore.tabbar_restore_clicked", true);
-        });
-      }
       Services.obs.addObserver(this, "sessionstore-last-session-cleared", true);
       goSetCommandEnabled("Browser:RestoreLastSession", true);
     } else if (SessionStartup.isAutomaticRestoreEnabled()) {
       document.getElementById("Browser:RestoreLastSession").setAttribute("hidden", true);
     }
   },
 
-  handleEvent(event) {
-    switch (event.type) {
-     case "TabOpen":
-        this.removeRestoreButton();
-        break;
-    }
-  },
-
-  removeRestoreButton() {
-    let {restoreTabsButton} = gBrowser.tabContainer;
-    let restoreTabsButtonWrapper = restoreTabsButton.parentNode;
-    gBrowser.tabContainer.addEventListener("transitionend", function maxWidthTransitionHandler(e) {
-      if (e.target == gBrowser.tabContainer && e.propertyName == "max-width") {
-        gBrowser.tabContainer.updateSessionRestoreVisibility();
-        gBrowser.tabContainer.removeEventListener("transitionend", maxWidthTransitionHandler);
-      }
-    });
-    restoreTabsButtonWrapper.removeAttribute("session-exists");
-    restoreTabsButton.style.maxWidth = 0;
-    gBrowser.tabContainer.removeEventListener("TabOpen", this);
-  },
-
   observe() {
     // The last session can only be restored once so there's
     // no way we need to re-enable our menu item.
     Services.obs.removeObserver(this, "sessionstore-last-session-cleared");
     goSetCommandEnabled("Browser:RestoreLastSession", false);
-    this.removeRestoreButton();
   },
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver,
                                          Ci.nsISupportsWeakReference])
 };
 
 function restoreLastSession() {
   SessionStore.restoreLastSession();

--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -90,36 +90,26 @@
   button, necessary due to the previous hack.
 -->
         <children/>
         <xul:toolbarbutton class="tabs-newtab-button toolbarbutton-1"
                            anonid="tabs-newtab-button"
                            command="cmd_newNavigatorTab"
                            onclick="checkForMiddleClick(this, event);"
                            tooltip="dynamic-shortcut-tooltip"/>
-        <xul:hbox class="restore-tabs-button-wrapper"
-                  anonid="restore-tabs-button-wrapper">
-          <xul:toolbarbutton anonid="restore-tabs-button"
-                             class="restore-tabs-button"
-                             onclick="SessionStore.restoreLastSession();"/>
-        </xul:hbox>
-
         <xul:spacer class="closing-tabs-spacer" anonid="closing-tabs-spacer"
                     style="width: 0;"/>
       </xul:arrowscrollbox>
     </content>
 
     <implementation implements="nsIDOMEventListener, nsIObserver">
       <constructor>
         <![CDATA[
           this._tabClipWidth = Services.prefs.getIntPref("browser.tabs.tabClipWidth");
 
-          let { restoreTabsButton } = this;
-          restoreTabsButton.setAttribute("label", gTabBrowserBundle.GetStringFromName("tabs.restoreLastTabs"));
-
           let strId = PrivateBrowsingUtils.isWindowPrivate(window) ?
               "emptyPrivateTabTitle" : "emptyTabTitle";
           this.emptyTabTitle = gTabBrowserBundle.GetStringFromName("tabs." + strId);
 
           var tab = this.firstChild;
           tab.label = this.emptyTabTitle;
           tab.setAttribute("onerror", "this.removeAttribute('image');");
 
@@ -170,76 +160,24 @@
       </field>
 
       <field name="_firstTab">null</field>
       <field name="_lastTab">null</field>
       <field name="_beforeSelectedTab">null</field>
       <field name="_beforeHoveredTab">null</field>
       <field name="_afterHoveredTab">null</field>
       <field name="_hoveredTab">null</field>
-      <field name="restoreTabsButton">
-        document.getAnonymousElementByAttribute(this, "anonid", "restore-tabs-button");
-      </field>
-      <field name="_restoreTabsButtonWrapperWidth">0</field>
-      <field name="windowUtils">
-        window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
-      </field>
 
       <property name="_tabMinWidth">
         <setter>
           this.style.setProperty("--tab-min-width", val + "px");
           return val;
         </setter>
       </property>
 
-      <property name="restoreTabsButtonWrapperWidth" readonly="true">
-        <getter>
-          if (!this._restoreTabsButtonWrapperWidth) {
-            this._restoreTabsButtonWrapperWidth = this.windowUtils
-              .getBoundsWithoutFlushing(this.restoreTabsButton.parentNode)
-              .width;
-          }
-          return this._restoreTabsButtonWrapperWidth;
-        </getter>
-      </property>
-
-      <method name="updateSessionRestoreVisibility">
-        <body><![CDATA[
-          let {restoreTabsButton, restoreTabsButtonWrapperWidth, windowUtils} = this;
-          let restoreTabsButtonWrapper = restoreTabsButton.parentNode;
-
-          if (!restoreTabsButtonWrapper.getAttribute("session-exists")) {
-            restoreTabsButtonWrapper.removeAttribute("shown");
-            return;
-          }
-
-          let arrowScrollboxWidth = this.arrowScrollbox.clientWidth;
-
-          let newTabButton = document.getAnonymousElementByAttribute(
-            this, "anonid", "tabs-newtab-button");
-
-          // If there are no pinned tabs it will multiply by 0 and result in 0
-          let pinnedTabsWidth = windowUtils.getBoundsWithoutFlushing(this.firstChild).width * this._lastNumPinned;
-
-          let numUnpinnedTabs = this.childNodes.length - this._lastNumPinned;
-          let unpinnedTabsWidth = windowUtils.getBoundsWithoutFlushing(this.lastChild).width * numUnpinnedTabs;
-
-          let tabbarUsedSpace = pinnedTabsWidth + unpinnedTabsWidth
-            + windowUtils.getBoundsWithoutFlushing(newTabButton).width;
-
-          // Subtract the elements' widths from the available space to ensure
-          // that showing the restoreTabsButton won't cause any overflow.
-          if (arrowScrollboxWidth - tabbarUsedSpace > restoreTabsButtonWrapperWidth) {
-            restoreTabsButtonWrapper.setAttribute("shown", "true");
-          } else {
-            restoreTabsButtonWrapper.removeAttribute("shown");
-          }
-        ]]></body>
-      </method>
-
       <method name="observe">
         <parameter name="aSubject"/>
         <parameter name="aTopic"/>
         <parameter name="aData"/>
         <body><![CDATA[
           switch (aTopic) {
             case "nsPref:changed":
               // This is has to deal with changes in
@@ -723,17 +661,16 @@
         <body><![CDATA[
           switch (aEvent.type) {
             case "resize":
               if (aEvent.target != window)
                 break;
 
               this._updateCloseButtons();
               this._handleTabSelect(true);
-              this.updateSessionRestoreVisibility();
               break;
             case "mouseout":
               // If the "related target" (the node to which the pointer went) is not
               // a child of the current document, the mouse just left the window.
               let relatedTarget = aEvent.relatedTarget;
               if (relatedTarget && relatedTarget.ownerDocument == document)
                 break;
             case "mousemove":

--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -3503,20 +3503,16 @@ var SessionStoreInternal = {
     if (winData.tabs.length) {
       this.restoreTabs(aWindow, tabs, winData.tabs, selectTab);
     }
 
     // set smoothScroll back to the original value
     arrowScrollbox.smoothScroll = smoothScroll;
 
     TelemetryStopwatch.finish("FX_SESSION_RESTORE_RESTORE_WINDOW_MS");
-    if (Services.prefs.getIntPref("browser.tabs.restorebutton") != 0 ) {
-      Services.telemetry.scalarAdd("browser.session.restore.number_of_tabs", winData.tabs.length);
-      Services.telemetry.scalarAdd("browser.session.restore.number_of_win", 1);
-    }
 
     this._setWindowStateReady(aWindow);
 
     this._sendWindowRestoredNotification(aWindow);
 
     Services.obs.notifyObservers(aWindow, NOTIFY_SINGLE_WINDOW_RESTORED);
 
     this._sendRestoreCompletedNotifications();

--- a/browser/locales/en-US/chrome/browser/tabbrowser.properties
+++ b/browser/locales/en-US/chrome/browser/tabbrowser.properties
@@ -1,13 +1,12 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-tabs.restoreLastTabs=Restore Tabs From Last Time
 tabs.emptyTabTitle=New Tab
 tabs.emptyPrivateTabTitle=Private Browsing
 tabs.closeTab=Close Tab
 tabs.close=Close
 tabs.closeWarningTitle=Confirm close
 # LOCALIZATION NOTE (tabs.closeWarningMultiple):
 # Semicolon-separated list of plural forms. See:
 # http://developer.mozilla.org/en/docs/Localization_and_Plurals

--- a/browser/modules/BrowserUITelemetry.jsm
+++ b/browser/modules/BrowserUITelemetry.jsm
@@ -125,17 +125,16 @@ XPCOMUtils.defineLazyGetter(this, "ALL_B
     "zoom-out-button",
     "zoom-reset-button",
     "zoom-in-button",
     "BMB_bookmarksPopup",
     "BMB_unsortedBookmarksPopup",
     "BMB_bookmarksToolbarPopup",
     "search-go-button",
     "soundplaying-icon",
-    "restore-tabs-button",
   ];
   return DEFAULT_ITEMS.concat(PALETTE_ITEMS)
                       .concat(SPECIAL_CASES);
 });
 
 const OTHER_MOUSEUP_MONITORED_ITEMS = [
   "PlacesChevron",
   "PlacesToolbarItems",

--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -623,21 +623,16 @@ notification[value="translation"] menuli
   overflow: hidden;
 }
 
 .webextension-popup-browser,
 .webextension-popup-stack {
   border-radius: inherit;
 }
 
-/* Prevent movement in the restore-tabs-button when it's clicked. */
-.restore-tabs-button:hover:active:not([disabled="true"]) {
-  padding: 3px;
-}
-
 /* Hide the titlebar explicitly on versions of GTK+ where
  * it's rendered by window manager. */
 @media (-moz-gtk-csd-available: 0) {
   #titlebar {
     display: none;
   }
 }
 

--- a/browser/themes/shared/tabs.inc.css
+++ b/browser/themes/shared/tabs.inc.css
@@ -743,60 +743,8 @@
 .alltabs-endimage[muted] {
   list-style-image: url(chrome://browser/skin/tabbrowser/tab-audio-muted.svg);
 }
 
 .alltabs-endimage[activemedia-blocked] {
   list-style-image: url(chrome://browser/skin/tabbrowser/tab-audio-blocked.svg);
 }
 
-.restore-tabs-button-wrapper {
-  visibility: hidden;
-  position: fixed; /* so the button does not take up actual space and cause overflow buttons in the tabbar when hidden */
-}
-
-.restore-tabs-button-wrapper[shown] {
-  visibility: visible;
-  position: initial;
-}
-
-.restore-tabs-button {
-  box-sizing: border-box;
-  -moz-appearance: none;
-  background-color: hsl(0,0%,0%,.04);
-  border: 1px solid hsla(0,0%,16%,.2);
-  border-radius: 3px;
-  margin: 3px;
-  margin-inline-start: 9px;
-  transition: max-width 100ms;
-  padding: 0 5px;
-}
-
-.restore-tabs-button:hover {
-  background-color: hsl(0,0%,0%,.08);
-}
-
-.restore-tabs-button:active {
-  background-color: hsl(0,0%,0%,.11);
-}
-
-#TabsToolbar[brighttext] .restore-tabs-button {
-  background-color: hsl(0,0%,100%,.07);
-  border-color:currentColor;
-  color: currentColor;
-  opacity: .7;
-}
-
-#TabsToolbar[brighttext] .restore-tabs-button:hover {
-  background-color: hsl(0,0%,100%,.17);
-}
-
-#TabsToolbar[brighttext] .restore-tabs-button:active {
-  background-color: hsl(0,0%,100%,.27);
-}
-
-.restore-tabs-button > .toolbarbutton-icon {
-  display: none;
-}
-
-.restore-tabs-button > .toolbarbutton-text {
-  display: -moz-box;
-}

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -1110,12 +1110,8 @@ panel[touchmode] .PanelUI-subView #appMe
 #ContentSelectDropdown > .isOpenedViaTouch > menucaption > .menu-iconic-text,
 #ContentSelectDropdown > .isOpenedViaTouch > menuitem > .menu-iconic-text {
   /* Touch padding should follow the 11/12 ratio, where 12px is the default
      font-size with 11px being the preferred padding size. */
   padding-top: .9167em;
   padding-bottom: .9167em;
 }
 
-/* Prevent movement in the restore-tabs-button when it's clicked. */
-.restore-tabs-button:hover:active:not([disabled="true"]) {
-  padding: 3px;
-}

--- a/testing/firefox-ui/tests/functional/sessionstore/manifest.ini
+++ b/testing/firefox-ui/tests/functional/sessionstore/manifest.ini
@@ -1,6 +1,4 @@
 [DEFAULT]
 tags = local
 
-[test_tabbar_session_restore_button.py]
-skip-if = os == "mac" # Bug 1396803
 [test_restore_windows_after_restart_and_quit.py]

deleted file mode 100644
--- a/testing/firefox-ui/tests/functional/sessionstore/test_tabbar_session_restore_button.py
+++ /dev/null
@@ -1,106 +0,0 @@
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-from firefox_puppeteer import PuppeteerMixin
-from marionette_harness import MarionetteTestCase
-from marionette_driver import Wait
-
-
-class TestBaseTabbarSessionRestoreButton(PuppeteerMixin, MarionetteTestCase):
-    def setUp(self, restore_button_pref=1):
-        super(TestBaseTabbarSessionRestoreButton, self).setUp()
-        self.marionette.enforce_gecko_prefs({'browser.tabs.restorebutton': restore_button_pref})
-
-        # Each list element represents a window of tabs loaded at
-        # some testing URL, the URLS are arbitrary.
-        self.test_windows = set([
-            (self.marionette.absolute_url('layout/mozilla_projects.html'),
-             self.marionette.absolute_url('layout/mozilla.html'),
-             self.marionette.absolute_url('layout/mozilla_mission.html')),
-        ])
-
-        self.open_windows(self.test_windows)
-
-        self.marionette.quit(in_app=True)
-        self.marionette.start_session()
-        self.marionette.set_context('chrome')
-
-    def open_windows(self, window_sets):
-        win = self.browser
-        for index, urls in enumerate(window_sets):
-            if index > 0:
-                win = self.browser.open_browser()
-            win.switch_to()
-            self.open_tabs(win, urls)
-
-    def open_tabs(self, win, urls):
-        # If there are any remaining URLs for this window,
-        # open some new tabs and navigate to them.
-        with self.marionette.using_context('content'):
-            if isinstance(urls, str):
-                self.marionette.navigate(urls)
-            else:
-                for index, url in enumerate(urls):
-                    if index > 0:
-                        with self.marionette.using_context('chrome'):
-                            win.tabbar.open_tab()
-                    self.marionette.navigate(url)
-
-    def tearDown(self):
-        try:
-            # Create a fresh profile for subsequent tests.
-            self.restart(clean=True)
-        finally:
-            super(TestBaseTabbarSessionRestoreButton, self).tearDown()
-
-
-class TestTabbarSessionRestoreButton(TestBaseTabbarSessionRestoreButton):
-    def setUp(self):
-        super(TestTabbarSessionRestoreButton, self).setUp()
-
-    def test_session_exists(self):
-        wrapper = self.puppeteer.windows.current.tabbar.restore_tabs_button_wrapper
-
-        # A session-exists attribute has been added to the button,
-        # which allows it to show.
-        self.assertEqual(wrapper.get_attribute('session-exists'), 'true')
-
-    def test_window_resizing(self):
-        wrapper = self.puppeteer.windows.current.tabbar.restore_tabs_button_wrapper
-
-        # Ensure the window is large enough to show the button.
-        self.marionette.set_window_size(1200, 1200)
-        self.assertEqual(wrapper.value_of_css_property('visibility'), 'visible')
-
-        # Set the window small enough that the button disappears.
-        self.marionette.set_window_size(335, 335)
-        self.assertEqual(wrapper.value_of_css_property('visibility'), 'hidden')
-
-    def test_click_restore(self):
-        button = self.puppeteer.windows.current.tabbar.restore_tabs_button
-
-        # The new browser window is not the same window as last time,
-        # and did not automatically restore the session, so there is only one tab.
-        self.assertEqual(len(self.puppeteer.windows.current.tabbar.tabs), 1)
-
-        button.click()
-
-        Wait(self.marionette, timeout=20).until(
-            lambda _: len(self.puppeteer.windows.current.tabbar.tabs) > 1,
-            message='there is only one tab, so the session was not restored')
-
-        # After clicking the button to restore the session,
-        # there is more than one tab.
-        self.assertTrue(len(self.puppeteer.windows.current.tabbar.tabs) > 1)
-
-
-class TestNoTabbarSessionRestoreButton(TestBaseTabbarSessionRestoreButton):
-    def setUp(self):
-        super(TestNoTabbarSessionRestoreButton, self).setUp(restore_button_pref=0)
-
-    def test_pref_off_button_does_not_show(self):
-        wrapper = self.puppeteer.windows.current.tabbar.restore_tabs_button_wrapper
-
-        # A session-exists attribute is not on the button,
-        # since the button will never show itself with the pref off.
-        self.assertEqual(wrapper.get_attribute('session-exists'), '')

--- a/testing/marionette/puppeteer/firefox/firefox_puppeteer/ui/browser/tabbar.py
+++ b/testing/marionette/puppeteer/firefox/firefox_puppeteer/ui/browser/tabbar.py
@@ -34,33 +34,16 @@ class TabBar(UIBaseLib):
     def newtab_button(self):
         """The DOM element which represents the new tab button.
 
         :returns: Reference to the new tab button.
         """
         return self.toolbar.find_element(By.ANON_ATTRIBUTE, {'anonid': 'tabs-newtab-button'})
 
     @property
-    def restore_tabs_button(self):
-        """The DOM element which represents the restore tabs button.
-
-        :returns: Reference to the restore tabs button.
-        """
-        return self.toolbar.find_element(By.ANON_ATTRIBUTE, {'anonid': 'restore-tabs-button'})
-
-    @property
-    def restore_tabs_button_wrapper(self):
-        """The DOM element which represents the restore tabs button wrapper.
-
-        :returns: Reference to the restore tabs button wrapper.
-        """
-        return self.toolbar.find_element(
-            By.ANON_ATTRIBUTE, {'anonid': 'restore-tabs-button-wrapper'})
-
-    @property
     def tabs(self):
         """List of all the :class:`Tab` instances of the current browser window.
 
         :returns: List of :class:`Tab` instances.
         """
         tabs = self.toolbar.find_elements(By.TAG_NAME, 'tab')
 
         return [Tab(self.marionette, self.window, tab) for tab in tabs]

--- a/toolkit/components/telemetry/Scalars.yaml
+++ b/toolkit/components/telemetry/Scalars.yaml
@@ -356,98 +356,16 @@ browser.usage:
       - bsmedberg@mozilla.com
     release_channel_collection: opt-out
     record_in_processes:
       - 'main'
       - 'content'
 
 # The following section contains the session restore scalars.
 browser.session.restore:
-  number_of_win:
-    bug_numbers:
-      - 1379226
-    description: The count of windows open after a session has been restored.
-    expires: never
-    kind: uint
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
-  number_of_tabs:
-    bug_numbers:
-      - 1379226
-    description: The count of tabs open after a session has been restored.
-    expires: never
-    kind: uint
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
-  tabbar_restore_available:
-    bug_numbers:
-      - 1379226
-    description: >
-      Recorded on startup. Boolean stating whether the tabbar session
-      restore button was ever available.
-    expires: never
-    kind: boolean
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
-  tabbar_restore_clicked:
-    bug_numbers:
-      - 1379226
-    description: >
-      Recorded on click event. Boolean stating if the session restore button
-      was clicked.
-    expires: never
-    kind: boolean
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
-  browser_startup_page:
-    bug_numbers:
-      - 1379226
-    description: >
-      The value of the browser.startup.page pref.
-      This pref restores the tabs and windows automatically when set to 3.
-    expires: never
-    kind: uint
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
-  browser_tabs_restorebutton:
-    bug_numbers:
-      - 1379226
-    description: >
-      The value of the browser.tabs.restorebutton pref.
-      0 - the user is not a part of the experiment
-      1 - the user is a part of the experiment
-      2 - the user is part of the control group
-    expires: never
-    kind: uint
-    notification_emails:
-      - bwinton@mozilla.com
-    release_channel_collection: opt-out
-    record_in_processes:
-      - 'main'
-
   worker_restart_count:
     bug_numbers:
       - 1402267
     description: >
       A counter incremented every time the SessionFile worker is restarted due
       to too many failures, as defined in the browser.sessionstore.max_write_failures
       pref.
     expires: "64"