--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -11,16 +11,17 @@
 #include "mozilla/layers/ISurfaceAllocator.h"     // for GfxMemoryImageReporter
 #include "mozilla/Telemetry.h"
 #include "mozilla/TimeStamp.h"
 
 #include "mozilla/Logging.h"
 #include "mozilla/Services.h"
 #include "prprf.h"
 
+#include "gfxCrashReporterUtils.h"
 #include "gfxPlatform.h"
 #include "gfxPrefs.h"
 #include "gfxEnv.h"
 #include "gfxTextRun.h"
 
 #ifdef XP_WIN
 #include <process.h>
 #define getpid _getpid
@@ -510,16 +511,54 @@ gfxPlatform::Init()
     gEverInitialized = true;
 
     // Initialize the preferences by creating the singleton.
     gfxPrefs::GetSingleton();
 
     auto fwd = new CrashStatsLogForwarder("GraphicsCriticalError");
     fwd->SetCircularBufferSize(gfxPrefs::GfxLoggingCrashLength());
 
+    // Drop a note in the crash report if we end up forcing an option that could
+    // destabilize things.  New items should be appended at the end (of an existing
+    // or in a new section), so that we don't have to know the version to interpret
+    // these cryptic strings.
+    {
+      nsAutoCString forcedPrefs;
+      // D2D prefs
+      forcedPrefs.AppendPrintf("FP(D%d%d%d",
+                               gfxPrefs::Direct2DDisabled(),
+                               gfxPrefs::Direct2DForceEnabled(),
+                               gfxPrefs::DirectWriteFontRenderingForceEnabled());
+      // Layers prefs
+      forcedPrefs.AppendPrintf("-L%d%d%d%d%d%d",
+                               gfxPrefs::LayersAMDSwitchableGfxEnabled(),
+                               gfxPrefs::LayersAccelerationDisabled(),
+                               gfxPrefs::LayersAccelerationForceEnabled(),
+                               gfxPrefs::LayersD3D11DisableWARP(),
+                               gfxPrefs::LayersD3D11ForceWARP(),
+                               gfxPrefs::LayersOffMainThreadCompositionForceEnabled());
+      // WebGL prefs
+      forcedPrefs.AppendPrintf("-W%d%d%d%d%d%d%d%d",
+                               gfxPrefs::WebGLANGLEForceD3D11(),
+                               gfxPrefs::WebGLANGLEForceWARP(),
+                               gfxPrefs::WebGLDisabled(),
+                               gfxPrefs::WebGLDisableANGLE(),
+                               gfxPrefs::WebGLDXGLEnabled(),
+                               gfxPrefs::WebGLForceEnabled(),
+                               gfxPrefs::WebGLForceLayersReadback(),
+                               gfxPrefs::WebGLForceMSAA());
+      // Prefs that don't fit into any of the other sections
+      forcedPrefs.AppendPrintf("-T%d%d%d%d) ",
+                               gfxPrefs::AndroidRGB16Force(),
+                               gfxPrefs::CanvasAzureAccelerated(),
+                               gfxPrefs::DisableGralloc(),
+                               gfxPrefs::ForceShmemTiles());
+      ScopedGfxFeatureReporter::AppNote(forcedPrefs);
+    }
+
     mozilla::gfx::Config cfg;
     cfg.mLogForwarder = fwd;
     cfg.mMaxTextureSize = gfxPrefs::MaxTextureSize();
     cfg.mMaxAllocSize = gfxPrefs::MaxAllocSize();
 
     gfx::Factory::Init(cfg);
 
     gGfxPlatformPrefsLock = new Mutex("gfxPlatform::gGfxPlatformPrefsLock");