JPEG 2000 Part 2 (Extended)

import magic
print(magic.from_file('image.jpx', mime=True)) # May default to generic 'image/jp2' depending on libmagic configuration

const FileType = require('file-type');
const type = await FileType.fromFile('image.jpx');
console.log(type?.mime); // Standard libraries may struggle to distinguish JPX from JP2

import "net/http"
// Custom ISOBMFF parsing is required to read the 'jpx ' brand inside the ftyp box.

$mime = mime_content_type('image.jpx');
echo $mime; // Standard implementations often map this to application/octet-stream or image/jp2