diff --git a/browser/themes/shared/incontent-icons/cert-error.svg b/browser/themes/shared/incontent-icons/cert-error.svg
index 4bf507791bc..9d23267bb0a 100644
--- a/browser/themes/shared/incontent-icons/cert-error.svg
+++ b/browser/themes/shared/incontent-icons/cert-error.svg
@@ -1,5 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
 
 <svg version="1.1"
      xmlns="http://www.w3.org/2000/svg"