diff --git a/dom/svg/SVGTests.h b/dom/svg/SVGTests.h
index 500af1c58fc0..0cbca71a2947 100644
--- a/dom/svg/SVGTests.h
+++ b/dom/svg/SVGTests.h
@@ -96,6 +96,7 @@ class SVGTests : public nsISupports {
   already_AddRefed<DOMSVGStringList> RequiredFeatures();
   already_AddRefed<DOMSVGStringList> RequiredExtensions();
   already_AddRefed<DOMSVGStringList> SystemLanguage();
+
   bool HasExtension(const nsAString& aExtension) const;
 
   virtual SVGElement* AsSVGElement() = 0;
diff --git a/dom/webidl/SVGTests.webidl b/dom/webidl/SVGTests.webidl
index e3c38242b38e..b97c61975e75 100644
--- a/dom/webidl/SVGTests.webidl
+++ b/dom/webidl/SVGTests.webidl
@@ -16,7 +16,5 @@ interface SVGTests {
   readonly attribute SVGStringList requiredFeatures;
   readonly attribute SVGStringList requiredExtensions;
   readonly attribute SVGStringList systemLanguage;
-
-  boolean hasExtension(DOMString extension);
 };
 
diff --git a/layout/mathml/tests/test_disabled_chrome.html b/layout/mathml/tests/test_disabled_chrome.html
index 294a8903bfbf..af97f2d4300e 100644
--- a/layout/mathml/tests/test_disabled_chrome.html
+++ b/layout/mathml/tests/test_disabled_chrome.html
@@ -42,9 +42,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=744830
 
     ok(chromeBR.height > contentBR.height, "Chrome content height should be bigger than content due to layout");
 
-    ok(!iframeEl.contentDocument.getElementById('svgel').hasExtension("http://www.w3.org/1998/Math/MathML"), 'SVG namespace support is disabled in content iframe');
-    ok(chromeIframeEl.contentDocument.getElementById('svgel').hasExtension("http://www.w3.org/1998/Math/MathML"), 'SVG namespace support is enabled in chrome iframe');
-
     SpecialPowers.setBoolPref("mathml.disabled", initialPrefValue);
   });
 </script>
diff --git a/layout/svg/tests/test_disabled_chrome.html b/layout/svg/tests/test_disabled_chrome.html
index 8a503a888e89..caff052877b7 100644
--- a/layout/svg/tests/test_disabled_chrome.html
+++ b/layout/svg/tests/test_disabled_chrome.html
@@ -38,9 +38,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=744830
     const contentBR = iframeEl.contentDocument.body.getBoundingClientRect();
     ok(chromeBR.height > contentBR.height, "Chrome content height should be bigger than content due to layout");
 
-    ok(!("hasExtension" in iframeEl.contentDocument.getElementById('svgel')), 'SVG is disabled so no hasExtension support is available in content iframe');
-    ok(chromeIframeEl.contentDocument.getElementById('svgel').hasExtension("http://www.w3.org/1998/Math/MathML"), 'SVG namespace support is enabled in chrome iframe');
-
     url = "http://mochi.test:8888/chrome/layout/svg/tests/svg_example_script.svg";
     const iframeElScript = document.createElement("iframe");
     let loadPromiseScript = ContentTaskUtils.waitForEvent(iframeElScript, "load", false);
diff --git a/testing/web-platform/meta/mathml/relations/html5-tree/required-extensions-1.html.ini b/testing/web-platform/meta/mathml/relations/html5-tree/required-extensions-1.html.ini
new file mode 100644
index 000000000000..7225765c034b
--- /dev/null
+++ b/testing/web-platform/meta/mathml/relations/html5-tree/required-extensions-1.html.ini
@@ -0,0 +1,4 @@
+[required-extensions-1.html]
+  [Testing foreignObject.hasExtension('http://www.w3.org/1998/Math/MathML')]
+    expected: FAIL
+
diff --git a/testing/web-platform/meta/svg/historical.html.ini b/testing/web-platform/meta/svg/historical.html.ini
index bbfd65c4c484..681ca1c5fa84 100644
--- a/testing/web-platform/meta/svg/historical.html.ini
+++ b/testing/web-platform/meta/svg/historical.html.ini
@@ -8,9 +8,6 @@
   [SVGGraphicsElement.prototype.getTransformToElement must be removed]
     expected: FAIL
 
-  [SVGGraphicsElement.prototype.hasExtension must be removed]
-    expected: FAIL
-
   [SVGGraphicsElement.prototype.requiredFeatures must be removed]
     expected: FAIL