Bank Telecommunications Image Format

import magic
print(magic.from_file('check.btif', mime=True)) # Will likely default to 'application/octet-stream' due to lack of magic byte rules

const FileType = require('file-type');
const type = await FileType.fromFile('check.btif');
console.log(type?.mime); // Standard parsers will not recognize BTIF files

import "net/http"
// The standard net/http library cannot detect BTIF files. You must rely on the file extension mapping.

$mime = mime_content_type('check.btif');
echo $mime; // Standard server environments will map this to application/octet-stream