public static boolean isExtendedWebpHeader(
      final byte[] imageHeaderBytes, final int offset, final int headerSize) {
    return headerSize >= EXTENDED_WEBP_HEADER_LENGTH
        && matchBytePattern(imageHeaderBytes, offset + 12, WEBP_VP8X_BYTES);
  }
Checks whether underlying platform supports extended WebPs
fbcore/src/main/java/com/facebook/common/webp/WebpSupportStatus.java