diff --git a/src/Magnum/GL/Implementation/ContextState.cpp b/src/Magnum/GL/Implementation/ContextState.cpp
index 78a834a17..0de455e75 100644
--- a/src/Magnum/GL/Implementation/ContextState.cpp
+++ b/src/Magnum/GL/Implementation/ContextState.cpp
@@ -28,21 +28,44 @@
 #include <Corrade/Containers/StringView.h>
 
 #include "Magnum/GL/Context.h"
+#include "Magnum/GL/Extensions.h"
 
 namespace Magnum { namespace GL { namespace Implementation {
 
 using namespace Containers::Literals;
 
-ContextState::ContextState(Context& context, Containers::StaticArrayView<Implementation::ExtensionCount, const char*>) {
+ContextState::ContextState(Context& context, const Containers::StaticArrayView<Implementation::ExtensionCount, const char*> extensions) {
     #ifndef MAGNUM_TARGET_GLES
     if((context.detectedDriver() & Context::DetectedDriver::NVidia) &&
         !context.isDriverWorkaroundDisabled("nv-zero-context-profile-mask"_s))
     {
         isCoreProfileImplementation = &Context::isCoreProfileImplementationNV;
     } else isCoreProfileImplementation = &Context::isCoreProfileImplementationDefault;
-    #else
+    #endif
+
+    #ifdef MAGNUM_TARGET_WEBGL
+    /* The rendererStringUnmasked() and vendorStringUnmasked() branch on the
+       extension on their own, which is in-line with all other "limit" queries.
+       It wouldn't make sense to create four new *Implementation()
+       functions and two new pointers for something that gets called mostly
+       just on application startup (and where it can't actually use the
+       function pointer because at that point the state is still yet to be
+       created).
+
+       But since there's nothing else would add the extension to the used
+       extension list, we're doing that here. */
+    if(context.isExtensionSupported<Extensions::WEBGL::debug_renderer_info>()) {
+        extensions[Extensions::WEBGL::debug_renderer_info::Index] =
+                   Extensions::WEBGL::debug_renderer_info::string();
+    }
+    #endif
+
+    #if defined(MAGNUM_TARGET_GLES) && !defined(MAGNUM_TARGET_WEBGL)
     static_cast<void>(context);
     #endif
+    #ifndef MAGNUM_TARGET_WEBGL
+    static_cast<void>(extensions);
+    #endif
 }
 
 }}}