diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 2a75ac5e4..ec9bc6834 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -12479,7 +12479,29 @@ interface WebGLRenderingContext {
     getBufferParameter(target: number, pname: number): any;
     getContextAttributes(): WebGLContextAttributes;
     getError(): number;
-    getExtension(name: string): any;
+    getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
+    getExtension(extensionName: "EXT_texture_filter_anisotropic"): EXT_texture_filter_anisotropic | null;
+    getExtension(extensionName: "EXT_frag_depth"): EXT_frag_depth | null;
+    getExtension(extensionName: "EXT_shader_texture_lod"): EXT_shader_texture_lod | null;
+    getExtension(extensionName: "EXT_sRGB"): EXT_sRGB | null;
+    getExtension(extensionName: "OES_vertex_array_object"): OES_vertex_array_object | null;
+    getExtension(extensionName: "WEBGL_color_buffer_float"): WEBGL_color_buffer_float | null;
+    getExtension(extensionName: "WEBGL_compressed_texture_astc"): WEBGL_compressed_texture_astc | null;
+    getExtension(extensionName: "WEBGL_compressed_texture_s3tc_srgb"): WEBGL_compressed_texture_s3tc_srgb | null;
+    getExtension(extensionName: "WEBGL_debug_shaders"): WEBGL_debug_shaders | null;
+    getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
+    getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
+    getExtension(extensionName: "WEBGL_depth_texture"): WEBGL_depth_texture | null;
+    getExtension(extensionName: "WEBGL_debug_renderer_info"): WEBGL_debug_renderer_info | null;
+    getExtension(extensionName: "WEBGL_compressed_texture_s3tc"): WEBGL_compressed_texture_s3tc | null;
+    getExtension(extensionName: "OES_texture_half_float_linear"): OES_texture_half_float_linear | null;
+    getExtension(extensionName: "OES_texture_half_float"): OES_texture_half_float | null;
+    getExtension(extensionName: "OES_texture_float_linear"): OES_texture_float_linear | null;
+    getExtension(extensionName: "OES_texture_float"): OES_texture_float | null;
+    getExtension(extensionName: "OES_standard_derivatives"): OES_standard_derivatives | null;
+    getExtension(extensionName: "OES_element_index_uint"): OES_element_index_uint | null;
+    getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
+    getExtension(extensionName: string): any;
     getFramebufferAttachmentParameter(target: number, attachment: number, pname: number): any;
     getParameter(pname: number): any;
     getProgramInfoLog(program: WebGLProgram | null): string | null;
@@ -14627,6 +14649,128 @@ declare var HTMLSummaryElement: {
     new(): HTMLSummaryElement;
 };
 
+interface EXT_blend_minmax {
+    readonly MIN_EXT: number;
+    readonly MAX_EXT: number;
+}
+
+interface EXT_frag_depth {
+}
+
+interface EXT_shader_texture_lod {
+}
+
+interface EXT_sRGB {
+    readonly SRGB_EXT: number;
+    readonly SRGB_ALPHA_EXT: number;
+    readonly SRGB8_ALPHA8_EXT: number;
+    readonly FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT: number;
+}
+
+interface OES_vertex_array_object {
+    readonly VERTEX_ARRAY_BINDING_OES: number;
+    createVertexArrayOES(): WebGLVertexArrayObjectOES;
+    deleteVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES): void;
+    isVertexArrayOES(value: any): value is WebGLVertexArrayObjectOES;
+    bindVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES): void;
+}
+
+interface WebGLVertexArrayObjectOES {
+}
+
+interface WEBGL_color_buffer_float {
+    readonly RGBA32F_EXT: number;
+    readonly RGB32F_EXT: number;
+    readonly FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE_EXT: number;
+    readonly UNSIGNED_NORMALIZED_EXT: number;
+}
+
+interface WEBGL_compressed_texture_astc {
+    readonly COMPRESSED_RGBA_ASTC_4x4_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_5x4_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_5x5_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_6x5_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_6x6_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_8x5_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_8x6_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_8x8_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_10x5_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_10x6_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_10x8_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_10x10_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_12x10_KHR: number;
+    readonly COMPRESSED_RGBA_ASTC_12x12_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR: number;
+    readonly COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR: number;
+    getSupportedProfiles(): string[];
+}
+
+interface WEBGL_compressed_texture_s3tc_srgb {
+    readonly COMPRESSED_SRGB_S3TC_DXT1_EXT: number;
+    readonly COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT: number;
+    readonly COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT: number;
+    readonly COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT: number;
+}
+
+interface WEBGL_debug_shaders {
+    getTranslatedShaderSource(shader: WebGLShader): string;
+}
+
+interface WEBGL_draw_buffers {
+    readonly COLOR_ATTACHMENT0_WEBGL: number;
+    readonly COLOR_ATTACHMENT1_WEBGL: number;
+    readonly COLOR_ATTACHMENT2_WEBGL: number;
+    readonly COLOR_ATTACHMENT3_WEBGL: number;
+    readonly COLOR_ATTACHMENT4_WEBGL: number;
+    readonly COLOR_ATTACHMENT5_WEBGL: number;
+    readonly COLOR_ATTACHMENT6_WEBGL: number;
+    readonly COLOR_ATTACHMENT7_WEBGL: number;
+    readonly COLOR_ATTACHMENT8_WEBGL: number;
+    readonly COLOR_ATTACHMENT9_WEBGL: number;
+    readonly COLOR_ATTACHMENT10_WEBGL: number;
+    readonly COLOR_ATTACHMENT11_WEBGL: number;
+    readonly COLOR_ATTACHMENT12_WEBGL: number;
+    readonly COLOR_ATTACHMENT13_WEBGL: number;
+    readonly COLOR_ATTACHMENT14_WEBGL: number;
+    readonly COLOR_ATTACHMENT15_WEBGL: number;
+    readonly DRAW_BUFFER0_WEBGL: number;
+    readonly DRAW_BUFFER1_WEBGL: number;
+    readonly DRAW_BUFFER2_WEBGL: number;
+    readonly DRAW_BUFFER3_WEBGL: number;
+    readonly DRAW_BUFFER4_WEBGL: number;
+    readonly DRAW_BUFFER5_WEBGL: number;
+    readonly DRAW_BUFFER6_WEBGL: number;
+    readonly DRAW_BUFFER7_WEBGL: number;
+    readonly DRAW_BUFFER8_WEBGL: number;
+    readonly DRAW_BUFFER9_WEBGL: number;
+    readonly DRAW_BUFFER10_WEBGL: number;
+    readonly DRAW_BUFFER11_WEBGL: number;
+    readonly DRAW_BUFFER12_WEBGL: number;
+    readonly DRAW_BUFFER13_WEBGL: number;
+    readonly DRAW_BUFFER14_WEBGL: number;
+    readonly DRAW_BUFFER15_WEBGL: number;
+    readonly MAX_COLOR_ATTACHMENTS_WEBGL: number;
+    readonly MAX_DRAW_BUFFERS_WEBGL: number;
+    drawBuffersWEBGL(buffers: number[]): void;
+}
+
+interface WEBGL_lose_context {
+    loseContext(): void;
+    restoreContext(): void;
+}
+
 declare type EventListenerOrEventListenerObject = EventListener | EventListenerObject;
 
 interface DecodeErrorCallback {
diff --git a/inputfiles/addedTypes.json b/inputfiles/addedTypes.json
index 730cb3a82..dc900d056 100644
--- a/inputfiles/addedTypes.json
+++ b/inputfiles/addedTypes.json
@@ -1922,6 +1922,532 @@
         "extends": "HTMLElement",
         "flavor": "DOM"
     },
+    {
+        "kind": "interface",
+        "name": "EXT_blend_minmax",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "MIN_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "MAX_EXT",
+                "type": "number"
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "EXT_frag_depth",
+        "flavor": "DOM",
+        "properties": []
+    },
+    {
+        "kind": "interface",
+        "name": "EXT_shader_texture_lod",
+        "flavor": "DOM",
+        "properties": []
+    },
+    {
+        "kind": "interface",
+        "name": "EXT_sRGB",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "SRGB_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "SRGB_ALPHA_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "SRGB8_ALPHA8_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT",
+                "type": "number"
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "OES_vertex_array_object",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "VERTEX_ARRAY_BINDING_OES",
+                "type": "number"
+            }
+        ],
+        "methods": [
+            {
+                "name": "createVertexArrayOES",
+                "signatures": [
+                    "createVertexArrayOES(): WebGLVertexArrayObjectOES"
+                ]
+            },
+            {
+                "name": "deleteVertexArrayOES",
+                "signatures": [
+                    "deleteVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES): void"
+                ]
+            },
+            {
+                "name": "isVertexArrayOES",
+                "signatures": [
+                    "isVertexArrayOES(value: any): value is WebGLVertexArrayObjectOES"
+                ]
+            },
+            {
+                "name": "bindVertexArrayOES",
+                "signatures": [
+                    "bindVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES): void"
+                ]
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WebGLVertexArrayObjectOES",
+        "flavor": "DOM",
+        "properties": []
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_color_buffer_float",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "RGBA32F_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "RGB32F_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "UNSIGNED_NORMALIZED_EXT",
+                "type": "number"
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_compressed_texture_astc",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_4x4_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_5x4_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_5x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_6x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_6x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_8x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_8x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_8x8_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_10x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_10x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_10x8_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_10x10_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_12x10_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_RGBA_ASTC_12x12_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR",
+                "type": "number"
+            }
+        ],
+        "methods": [
+            {
+                "name": "getSupportedProfiles",
+                "signatures": [
+                    "getSupportedProfiles(): string[]"
+                ]
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_compressed_texture_s3tc_srgb",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB_S3TC_DXT1_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT",
+                "type": "number"
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_debug_shaders",
+        "flavor": "DOM",
+        "methods": [
+            {
+                "name": "getTranslatedShaderSource",
+                "signatures": [
+                    "getTranslatedShaderSource(shader: WebGLShader): string"
+                ]
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_draw_buffers",
+        "flavor": "DOM",
+        "properties": [
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT0_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT1_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT2_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT3_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT4_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT5_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT6_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT7_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT8_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT9_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT10_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT11_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT12_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT13_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT14_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "COLOR_ATTACHMENT15_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER0_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER1_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER2_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER3_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER4_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER5_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER6_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER7_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER8_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER9_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER10_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER11_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER12_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER13_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER14_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "DRAW_BUFFER15_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "MAX_COLOR_ATTACHMENTS_WEBGL",
+                "type": "number"
+            },
+            {
+                "readonly": true,
+                "name": "MAX_DRAW_BUFFERS_WEBGL",
+                "type": "number"
+            }
+        ],
+        "methods": [
+            {
+                "name": "drawBuffersWEBGL",
+                "signatures": [
+                    "drawBuffersWEBGL(buffers: number[]): void"
+                ]
+            }
+        ]
+    },
+    {
+        "kind": "interface",
+        "name": "WEBGL_lose_context",
+        "flavor": "DOM",
+        "methods": [
+            {
+                "name": "loseContext",
+                "signatures": [
+                    "loseContext(): void"
+                ]
+            },
+            {
+                "name": "restoreContext",
+                "signatures": [
+                    "restoreContext(): void"
+                ]
+            }
+        ]
+    },
     {
         "kind": "method",
         "interface": "HTMLFormElement",
diff --git a/inputfiles/overridingTypes.json b/inputfiles/overridingTypes.json
index f4a134d2a..44fc84e7b 100644
--- a/inputfiles/overridingTypes.json
+++ b/inputfiles/overridingTypes.json
@@ -1042,6 +1042,36 @@
             "vertexAttrib4fv(indx: number, values: Float32Array | number[]): void"
         ]
     },
+    {
+        "kind": "method",
+        "interface": "WebGLRenderingContext",
+        "name": "getExtension",
+        "signatures": [
+            "getExtension(extensionName: \"EXT_blend_minmax\"): EXT_blend_minmax | null",
+            "getExtension(extensionName: \"EXT_texture_filter_anisotropic\"): EXT_texture_filter_anisotropic | null",
+            "getExtension(extensionName: \"EXT_frag_depth\"): EXT_frag_depth | null",
+            "getExtension(extensionName: \"EXT_shader_texture_lod\"): EXT_shader_texture_lod | null",
+            "getExtension(extensionName: \"EXT_sRGB\"): EXT_sRGB | null",
+            "getExtension(extensionName: \"OES_vertex_array_object\"): OES_vertex_array_object | null",
+            "getExtension(extensionName: \"WEBGL_color_buffer_float\"): WEBGL_color_buffer_float | null",
+            "getExtension(extensionName: \"WEBGL_compressed_texture_astc\"): WEBGL_compressed_texture_astc | null",
+            "getExtension(extensionName: \"WEBGL_compressed_texture_s3tc_srgb\"): WEBGL_compressed_texture_s3tc_srgb | null",
+            "getExtension(extensionName: \"WEBGL_debug_shaders\"): WEBGL_debug_shaders | null",
+            "getExtension(extensionName: \"WEBGL_draw_buffers\"): WEBGL_draw_buffers | null",
+            "getExtension(extensionName: \"WEBGL_lose_context\"): WEBGL_lose_context | null",
+            "getExtension(extensionName: \"WEBGL_depth_texture\"): WEBGL_depth_texture | null",
+            "getExtension(extensionName: \"WEBGL_debug_renderer_info\"): WEBGL_debug_renderer_info | null",
+            "getExtension(extensionName: \"WEBGL_compressed_texture_s3tc\"): WEBGL_compressed_texture_s3tc | null",
+            "getExtension(extensionName: \"OES_texture_half_float_linear\"): OES_texture_half_float_linear | null",
+            "getExtension(extensionName: \"OES_texture_half_float\"): OES_texture_half_float | null",
+            "getExtension(extensionName: \"OES_texture_float_linear\"): OES_texture_float_linear | null",
+            "getExtension(extensionName: \"OES_texture_float\"): OES_texture_float | null",
+            "getExtension(extensionName: \"OES_standard_derivatives\"): OES_standard_derivatives | null",
+            "getExtension(extensionName: \"OES_element_index_uint\"): OES_element_index_uint | null",
+            "getExtension(extensionName: \"ANGLE_instanced_arrays\"): ANGLE_instanced_arrays | null",
+            "getExtension(extensionName: string): any"
+        ]
+    },
     {
         "kind": "method",
         "interface": "Element",
@@ -1660,4 +1690,4 @@
         "name": "supportedMethods",
         "type": "string | string[]"
     }
-]
+]
\ No newline at end of file