diff --git a/dom/locales/en-US/chrome/global.dtd b/dom/locales/en-US/chrome/global.dtd
deleted file mode 100644
index 661fb351f4c3..000000000000
--- a/dom/locales/en-US/chrome/global.dtd
+++ /dev/null
@@ -1,5 +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/. -->
-
-<!ENTITY locale.dir "ltr">
diff --git a/dom/locales/jar.mn b/dom/locales/jar.mn
index 02d80567c2e6..3aa7eb35edc0 100644
--- a/dom/locales/jar.mn
+++ b/dom/locales/jar.mn
@@ -11,7 +11,6 @@
   locale/@AB_CD@/global/xul.properties                         (%chrome/layout/xul.properties)
   locale/@AB_CD@/global/printing.properties                    (%chrome/layout/printing.properties)
   locale/@AB_CD@/global/layout_errors.properties               (%chrome/layout/layout_errors.properties)
-  locale/@AB_CD@/global/global.dtd                             (%chrome/global.dtd)
   locale/@AB_CD@/global/appstrings.properties                  (%chrome/appstrings.properties)
   locale/@AB_CD@/global/global-strres.properties               (%chrome/global-strres.properties)
   locale/@AB_CD@/global/nsWebBrowserPersist.properties         (%chrome/nsWebBrowserPersist.properties)
diff --git a/mobile/android/locales/filter.py b/mobile/android/locales/filter.py
index e9fed5e4cd0e..fd9252901beb 100644
--- a/mobile/android/locales/filter.py
+++ b/mobile/android/locales/filter.py
@@ -55,7 +55,6 @@ def test(mod, path, entity=None):
     if mod == "dom":
         # keep this file list in sync with jar.mn
         if path in (
-            "chrome/global.dtd",
             "chrome/accessibility/AccessFu.properties",
             "chrome/dom/dom.properties",
         ):
diff --git a/mobile/android/locales/jar.mn b/mobile/android/locales/jar.mn
index cb4efb03468c..87f28c3c04fe 100644
--- a/mobile/android/locales/jar.mn
+++ b/mobile/android/locales/jar.mn
@@ -23,7 +23,6 @@ relativesrcdir toolkit/locales:
 # overrides for dom l10n, also for en-US
 # keep this file list in sync with filter.py
 relativesrcdir dom/locales:
-  locale/@AB_CD@/browser/overrides/global.dtd                  (%chrome/global.dtd)
   locale/@AB_CD@/browser/overrides/AccessFu.properties         (%chrome/accessibility/AccessFu.properties)
   locale/@AB_CD@/browser/overrides/dom/dom.properties          (%chrome/dom/dom.properties)
 
diff --git a/mobile/android/locales/l10n.toml b/mobile/android/locales/l10n.toml
index ba41945d896d..29474fae0c1a 100644
--- a/mobile/android/locales/l10n.toml
+++ b/mobile/android/locales/l10n.toml
@@ -125,10 +125,6 @@ exclude-multi-locale = [
     l10n = "{l}mobile/android/**"
 
 # hand-picked paths from toolkit, keep in sync with jar.mn
-[[paths]]
-    reference = "dom/locales/en-US/chrome/global.dtd"
-    l10n = "{l}dom/chrome/global.dtd"
-
 [[paths]]
     reference = "dom/locales/en-US/chrome/accessibility/AccessFu.properties"
     l10n = "{l}dom/chrome/accessibility/AccessFu.properties"
diff --git a/mobile/locales/filter.py b/mobile/locales/filter.py
index 7c47a4a1001a..874da98cf785 100644
--- a/mobile/locales/filter.py
+++ b/mobile/locales/filter.py
@@ -56,7 +56,6 @@ def test(mod, path, entity=None):
     if mod == "dom":
         # keep this file list in sync with jar.mn
         if path in (
-            "chrome/global.dtd",
             "chrome/accessibility/AccessFu.properties",
             "chrome/dom/dom.properties",
         ):
diff --git a/toolkit/content/moz.build b/toolkit/content/moz.build
index 5d93d496408a..26ce408c81c5 100644
--- a/toolkit/content/moz.build
+++ b/toolkit/content/moz.build
@@ -145,11 +145,6 @@ with Files("tests/chrome/*418874*"):
 with Files("tests/chrome/*429723*"):
     BUG_COMPONENT = ("Toolkit", "Find Toolbar")
 
-with Files("tests/chrome/*437844*"):
-    BUG_COMPONENT = ("Toolkit", "General")
-with Files("tests/chrome/rtlchrome/**"):
-    BUG_COMPONENT = ("Toolkit", "General")
-
 with Files("tests/chrome/*451540*"):
     BUG_COMPONENT = ("Toolkit", "Find Toolbar")
 
diff --git a/toolkit/content/tests/chrome/chrome.ini b/toolkit/content/tests/chrome/chrome.ini
index 8e69343fb31a..a8895c0cca97 100644
--- a/toolkit/content/tests/chrome/chrome.ini
+++ b/toolkit/content/tests/chrome/chrome.ini
@@ -49,9 +49,6 @@ support-files =
   window_subframe_origin.xhtml
   window_tooltip.xhtml
   xul_selectcontrol.js
-  rtlchrome/rtl.css
-  rtlchrome/rtl.dtd
-  rtlchrome/rtl.manifest
 prefs =
   gfx.font_rendering.fallback.async=false
   widget.non-native-theme.enabled=false
@@ -84,8 +81,6 @@ skip-if = os == 'linux' # Bug 1264604
 [test_bug409624.xhtml]
 [test_bug418874.xhtml]
 [test_bug429723.xhtml]
-[test_bug437844.xhtml]
-skip-if = (verify && debug && (os == 'mac' || os == 'win'))
 [test_bug451540.xhtml]
 support-files = bug451540_window.xhtml
 [test_bug457632.xhtml]
diff --git a/toolkit/content/tests/chrome/rtlchrome/rtl.css b/toolkit/content/tests/chrome/rtlchrome/rtl.css
deleted file mode 100644
index 0fea0100196f..000000000000
--- a/toolkit/content/tests/chrome/rtlchrome/rtl.css
+++ /dev/null
@@ -1,2 +0,0 @@
-/* Imitate RTL UI */
-window { direction: rtl; }
diff --git a/toolkit/content/tests/chrome/rtlchrome/rtl.dtd b/toolkit/content/tests/chrome/rtlchrome/rtl.dtd
deleted file mode 100644
index 8b32de674673..000000000000
--- a/toolkit/content/tests/chrome/rtlchrome/rtl.dtd
+++ /dev/null
@@ -1 +0,0 @@
-<!ENTITY locale.dir "rtl">
diff --git a/toolkit/content/tests/chrome/rtlchrome/rtl.manifest b/toolkit/content/tests/chrome/rtlchrome/rtl.manifest
deleted file mode 100644
index a4cc6929be4a..000000000000
--- a/toolkit/content/tests/chrome/rtlchrome/rtl.manifest
+++ /dev/null
@@ -1,5 +0,0 @@
-content rtlchrome /
-
-# Override intl.css with our own CSS file
-override chrome://global/locale/intl.css chrome://rtlchrome/rtl.css
-override chrome://global/locale/global.dtd chrome://rtlchrome/rtl.dtd
diff --git a/toolkit/content/tests/chrome/test_bug437844.xhtml b/toolkit/content/tests/chrome/test_bug437844.xhtml
deleted file mode 100644
index 99186ef0cff9..000000000000
--- a/toolkit/content/tests/chrome/test_bug437844.xhtml
+++ /dev/null
@@ -1,89 +0,0 @@
-<?xml version="1.0"?>
-<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
-<?xml-stylesheet
-  href="chrome://mochikit/content/tests/SimpleTest/test.css"
-  type="text/css"?>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=437844
-https://bugzilla.mozilla.org/show_bug.cgi?id=348233
--->
-<window title="Mozilla Bug 437844 and Bug 348233"
-  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
-
-  <script type="application/javascript"
-          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript"
-          src="chrome://mochikit/content/chrome-harness.js"></script>
-  <script type="application/javascript"
-          src="RegisterUnregisterChrome.js"></script>
-
-  <body  xmlns="http://www.w3.org/1999/xhtml">
-    <a target="_blank"
-       href="https://bugzilla.mozilla.org/show_bug.cgi?id=437844">
-      Mozilla Bug 437844
-    </a>
-    <a target="_blank"
-       href="https://bugzilla.mozilla.org/show_bug.cgi?id=348233">
-      Mozilla Bug 348233
-    </a>
-
-    <p id="display"></p>
-    <div id="content" style="display: none">
-    </div>
-    <pre id="test">
-    </pre>
-  </body>
-
-  <script class="testbody" type="application/javascript">
-    <![CDATA[
-
-      SimpleTest.expectAssertions(0, 58);
-
-      /** Test for Bug 437844 and Bug 348233 **/
-      SimpleTest.waitForExplicitFinish();
-
-      let prefs = SpecialPowers.Services.prefs;
-      prefs.setCharPref("intl.l10n.pseudo", "bidi");
-
-      let rootDir = getRootDirectory(window.location.href);
-      let manifest = rootDir + "rtlchrome/rtl.manifest";
-
-      //copy rtlchrome to profile/rtlchrome and generate .manifest
-      let filePath = chromeURIToFile(manifest);
-      let tempProfileDir = copyDirToTempProfile(filePath.path, 'rtlchrome');
-      if (tempProfileDir.path.lastIndexOf('\\') >= 0) {
-        manifest = "content rtlchrome /" + tempProfileDir.path.replace(/\\/g, '/') + "\n";
-      } else {
-        manifest = "content rtlchrome " + tempProfileDir.path + "\n";
-      }
-      manifest += "override chrome://global/locale/intl.css chrome://rtlchrome/content/rtlchrome/rtl.css\n";
-      manifest += "override chrome://global/locale/global.dtd chrome://rtlchrome/content/rtlchrome/rtl.dtd\n";
-
-      let cleanupFunc = createManifestTemporarily(tempProfileDir, manifest);
-
-      // Load about:plugins in an iframe
-      let frame = document.createXULElement("iframe");
-      frame.setAttribute("src", "about:plugins");
-      frame.addEventListener("load", function () {
-          is(frame.contentDocument.dir, "rtl", "about:plugins should be RTL in RTL locales");
-
-          // eslint-disable-next-line no-unused-vars
-          let tmpd = SpecialPowers.Services.dirsvc.get("ProfD", Ci.nsIFile);
-
-          frame = document.createXULElement("iframe");
-          frame.setAttribute("src", "file://" + tmpd.path); // a file:// URI, bug 348233
-          frame.addEventListener("load", function () {
-              is(frame.contentDocument.body.dir, "rtl", "file:// listings should be RTL in RTL locales");
-
-              cleanupFunc();
-              prefs.clearUserPref("intl.l10n.pseudo");
-              SimpleTest.finish();
-            });
-          document.documentElement.appendChild(frame);
-        }, { once: true });
-      document.documentElement.appendChild(frame);
-
-    ]]>
-  </script>
-
-</window>