--- a/browser/confvars.sh
+++ b/browser/confvars.sh
@@ -50,17 +50,16 @@ MOZ_OFFICIAL_BRANDING_DIRECTORY=browser/
 MOZ_APP_ID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}
 # This should usually be the same as the value MAR_CHANNEL_ID.
 # If more than one ID is needed, then you should use a comma separated list
 # of values.
 ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-central
 # The MAR_CHANNEL_ID must not contain the following 3 characters: ",\t "
 MAR_CHANNEL_ID=firefox-mozilla-central
 MOZ_PROFILE_MIGRATOR=1
-MOZ_WEBGL_CONFORMANT=1
 MOZ_JSDOWNLOADS=1
 MOZ_RUST_MP4PARSE=1
 
 # Enable checking that add-ons are signed by the trusted root
 MOZ_ADDON_SIGNING=1
 
 # Include the DevTools client, not just the server (which is the default)
 MOZ_DEVTOOLS=all

--- a/dom/canvas/CanvasUtils.cpp
+++ b/dom/canvas/CanvasUtils.cpp
@@ -31,32 +31,23 @@ namespace CanvasUtils {
 bool
 GetCanvasContextType(const nsAString& str, dom::CanvasContextType* const out_type)
 {
   if (str.EqualsLiteral("2d")) {
     *out_type = dom::CanvasContextType::Canvas2D;
     return true;
   }
 
-  if (str.EqualsLiteral("experimental-webgl")) {
+  if (str.EqualsLiteral("webgl") ||
+      str.EqualsLiteral("experimental-webgl"))
+  {
     *out_type = dom::CanvasContextType::WebGL1;
     return true;
   }
 
-#ifdef MOZ_WEBGL_CONFORMANT
-  if (str.EqualsLiteral("webgl")) {
-    /* WebGL 1.0, $2.1 "Context Creation":
-     *   If the user agent supports both the webgl and experimental-webgl
-     *   canvas context types, they shall be treated as aliases.
-     */
-    *out_type = dom::CanvasContextType::WebGL1;
-    return true;
-  }
-#endif
-
   if (WebGL2Context::IsSupported()) {
     if (str.EqualsLiteral("webgl2")) {
       *out_type = dom::CanvasContextType::WebGL2;
       return true;
     }
   }
 
   if (str.EqualsLiteral("bitmaprenderer")) {

--- a/mobile/android/confvars.sh
+++ b/mobile/android/confvars.sh
@@ -43,16 +43,13 @@ MOZ_NATIVE_DEVICES=1
 # Enable install tracking SDK if we have Google Play support; MOZ_NATIVE_DEVICES
 # is a proxy flag for that support.
 if test "$RELEASE_OR_BETA"; then
 if test "$MOZ_NATIVE_DEVICES"; then
   MOZ_INSTALL_TRACKING=1
 fi
 fi
 
-# Mark as WebGL conformant
-MOZ_WEBGL_CONFORMANT=1
-
 # Use the low-memory GC tuning.
 export JS_GC_SMALL_CHUNK_SIZE=1
 
 # Enable checking that add-ons are signed by the trusted root
 MOZ_ADDON_SIGNING=1

--- a/old-configure.in
+++ b/old-configure.in
@@ -3207,23 +3207,16 @@ case "${target_cpu}" in
 i*86)
   MOZ_D3D_CPU_SUFFIX=x86
   ;;
 x86_64)
   MOZ_D3D_CPU_SUFFIX=x64
   ;;
 esac
 
-# This is potentially set in external mozconfig files; if it's set,
-# then the build exposes the "webgl" context name, which is reserved
-# for conformant implementations.
-if test -n "$MOZ_WEBGL_CONFORMANT"; then
-  AC_DEFINE(MOZ_WEBGL_CONFORMANT)
-fi
-
 dnl ========================================================
 dnl D3D compiler DLL
 dnl ========================================================
 MOZ_FOUND_D3D_COMPILERS=
 
 if test -n "$MOZ_ANGLE_RENDERER"; then
   if test -z "$MOZ_D3D_CPU_SUFFIX"; then
     AC_MSG_ERROR([Couldn't determine MOZ_D3D_CPU_SUFFIX.])