diff --git a/dom/canvas/WebGLContextExtensions.cpp b/dom/canvas/WebGLContextExtensions.cpp
index 9e89c3c5e81e..3b6c4f5fa5ec 100644
--- a/dom/canvas/WebGLContextExtensions.cpp
+++ b/dom/canvas/WebGLContextExtensions.cpp
@@ -32,6 +32,7 @@ WebGLContext::GetExtensionString(WebGLExtensionID ext)
 
         WEBGL_EXTENSION_IDENTIFIER(ANGLE_instanced_arrays)
         WEBGL_EXTENSION_IDENTIFIER(EXT_blend_minmax)
+        WEBGL_EXTENSION_IDENTIFIER(EXT_color_buffer_float)
         WEBGL_EXTENSION_IDENTIFIER(EXT_color_buffer_half_float)
         WEBGL_EXTENSION_IDENTIFIER(EXT_frag_depth)
         WEBGL_EXTENSION_IDENTIFIER(EXT_shader_texture_lod)
@@ -151,7 +152,18 @@ WebGLContext::IsExtensionSupported(WebGLExtensionID ext) const
         break;
     }
 
-    if (!IsWebGL2()) {
+    if (IsWebGL2()) {
+        // WebGL2-only extensions
+        switch (ext) {
+        // EXT_
+        case WebGLExtensionID::EXT_color_buffer_float:
+            return WebGLExtensionEXTColorBufferFloat::IsSupported(this);
+
+        default:
+            // For warnings-as-errors.
+            break;
+        }
+    } else {
         // WebGL1-only extensions
         switch (ext) {
         // ANGLE_
@@ -331,6 +343,9 @@ WebGLContext::EnableExtension(WebGLExtensionID ext)
     case WebGLExtensionID::EXT_blend_minmax:
         obj = new WebGLExtensionBlendMinMax(this);
         break;
+    case WebGLExtensionID::EXT_color_buffer_float:
+        obj = new WebGLExtensionEXTColorBufferFloat(this);
+        break;
     case WebGLExtensionID::EXT_color_buffer_half_float:
         obj = new WebGLExtensionColorBufferHalfFloat(this);
         break;
diff --git a/dom/canvas/WebGLExtensionEXTColorBufferFloat.cpp b/dom/canvas/WebGLExtensionEXTColorBufferFloat.cpp
new file mode 100644
index 000000000000..8061f6fc16e8
--- /dev/null
+++ b/dom/canvas/WebGLExtensionEXTColorBufferFloat.cpp
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WebGLExtensions.h"
+
+#include "GLContext.h"
+#include "mozilla/dom/WebGL2RenderingContextBinding.h"
+#include "WebGLContext.h"
+#include "WebGLFormats.h"
+
+namespace mozilla {
+
+WebGLExtensionEXTColorBufferFloat::WebGLExtensionEXTColorBufferFloat(WebGLContext* webgl)
+    : WebGLExtensionBase(webgl)
+{
+    MOZ_ASSERT(IsSupported(webgl), "Don't construct extension if unsupported.");
+
+    auto& fua = webgl->mFormatUsage;
+
+    auto fnUpdateUsage = [&fua](GLenum sizedFormat, webgl::EffectiveFormat effFormat) {
+        auto usage = fua->EditUsage(effFormat);
+        usage->isRenderable = true;
+        fua->AllowRBFormat(sizedFormat, usage);
+    };
+
+#define FOO(x) fnUpdateUsage(LOCAL_GL_ ## x, webgl::EffectiveFormat::x)
+
+    FOO(R16F);
+    FOO(RG16F);
+    FOO(RGBA16F);
+
+    FOO(R32F);
+    FOO(RG32F);
+    FOO(RGBA32F);
+
+    FOO(R11F_G11F_B10F);
+
+#undef FOO
+}
+
+/*static*/ bool
+WebGLExtensionEXTColorBufferFloat::IsSupported(const WebGLContext* webgl)
+{
+    const gl::GLContext* gl = webgl->GL();
+    return gl->IsSupported(gl::GLFeature::EXT_color_buffer_float);
+}
+
+IMPL_WEBGL_EXTENSION_GOOP(WebGLExtensionEXTColorBufferFloat, EXT_color_buffer_float)
+
+} // namespace mozilla
diff --git a/dom/canvas/WebGLExtensions.h b/dom/canvas/WebGLExtensions.h
index 39436025d359..221a92a5f526 100644
--- a/dom/canvas/WebGLExtensions.h
+++ b/dom/canvas/WebGLExtensions.h
@@ -153,6 +153,18 @@ public:
     DECL_WEBGL_EXTENSION_GOOP
 };
 
+class WebGLExtensionEXTColorBufferFloat
+    : public WebGLExtensionBase
+{
+public:
+    explicit WebGLExtensionEXTColorBufferFloat(WebGLContext*);
+    virtual ~WebGLExtensionEXTColorBufferFloat() { }
+
+    static bool IsSupported(const WebGLContext*);
+
+    DECL_WEBGL_EXTENSION_GOOP
+};
+
 class WebGLExtensionFragDepth
     : public WebGLExtensionBase
 {
diff --git a/dom/canvas/WebGLProgram.cpp b/dom/canvas/WebGLProgram.cpp
index d4f1115dbaf6..f7bb0e771fae 100644
--- a/dom/canvas/WebGLProgram.cpp
+++ b/dom/canvas/WebGLProgram.cpp
@@ -10,6 +10,7 @@
 #include "mozilla/dom/WebGL2RenderingContextBinding.h"
 #include "mozilla/dom/WebGLRenderingContextBinding.h"
 #include "mozilla/RefPtr.h"
+#include "nsPrintfCString.h"
 #include "WebGLActiveInfo.h"
 #include "WebGLContext.h"
 #include "WebGLShader.h"
diff --git a/dom/canvas/WebGLTypes.h b/dom/canvas/WebGLTypes.h
index 30abb9104041..fb7119d4b786 100644
--- a/dom/canvas/WebGLTypes.h
+++ b/dom/canvas/WebGLTypes.h
@@ -139,6 +139,7 @@ enum class WebGLTexDimensions : uint8_t {
 enum class WebGLExtensionID : uint8_t {
     ANGLE_instanced_arrays,
     EXT_blend_minmax,
+    EXT_color_buffer_float,
     EXT_color_buffer_half_float,
     EXT_frag_depth,
     EXT_sRGB,
diff --git a/dom/canvas/moz.build b/dom/canvas/moz.build
index 5251c95cbe56..30dee922169d 100644
--- a/dom/canvas/moz.build
+++ b/dom/canvas/moz.build
@@ -112,6 +112,7 @@ UNIFIED_SOURCES += [
     'WebGLExtensionDisjointTimerQuery.cpp',
     'WebGLExtensionDrawBuffers.cpp',
     'WebGLExtensionElementIndexUint.cpp',
+    'WebGLExtensionEXTColorBufferFloat.cpp',
     'WebGLExtensionFragDepth.cpp',
     'WebGLExtensionInstancedArrays.cpp',
     'WebGLExtensionLoseContext.cpp',
diff --git a/gfx/gl/GLContext.h b/gfx/gl/GLContext.h
index 284b9b1b034d..ea1c2968793c 100644
--- a/gfx/gl/GLContext.h
+++ b/gfx/gl/GLContext.h
@@ -95,6 +95,7 @@ enum class GLFeature {
     element_index_uint,
     ES2_compatibility,
     ES3_compatibility,
+    EXT_color_buffer_float,
     frag_color_float,
     frag_depth,
     framebuffer_blit,
diff --git a/gfx/gl/GLContextFeatures.cpp b/gfx/gl/GLContextFeatures.cpp
index d328e9f164ea..9e65c58c99a2 100644
--- a/gfx/gl/GLContextFeatures.cpp
+++ b/gfx/gl/GLContextFeatures.cpp
@@ -186,6 +186,16 @@ static const FeatureInfo sFeatureInfoArr[] = {
             GLContext::Extensions_End
         }
     },
+    {
+        "EXT_color_buffer_float",
+        GLVersion::GL3,
+        GLESVersion::NONE,
+        GLContext::Extension_None,
+        {
+            GLContext::EXT_color_buffer_float,
+            GLContext::Extensions_End
+        }
+    },
     {
         // Removes clamping for float color outputs from frag shaders.
         "frag_color_float",