WEBGL_compressed_texture_etc

readonly COMPRESSED_R11_EAC: GLenum;

readonly COMPRESSED_RG11_EAC: GLenum;

readonly COMPRESSED_RGB8_ETC2: GLenum;

readonly COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2: GLenum;

readonly COMPRESSED_RGBA8_ETC2_EAC: GLenum;

readonly COMPRESSED_SIGNED_R11_EAC: GLenum;

readonly COMPRESSED_SIGNED_RG11_EAC: GLenum;

readonly COMPRESSED_SRGB8_ALPHA8_ETC2_EAC: GLenum;

readonly COMPRESSED_SRGB8_ETC2: GLenum;

readonly COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2: GLenum;