Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Gnumeric.php
public function canRead($pFilename)
    {
        File::assertFile($pFilename);

        // Check if gzlib functions are available
        if (!function_exists('gzread')) {
            throw new Exception('gzlib library is not enabled');
        }

        // Read signature data (first 3 bytes)
        $fh = fopen($pFilename, 'r');
        $data = fread($fh, 2);
        fclose($fh);

        return $data == chr(0x1F) . chr(0x8B);
    }
public function canRead($pFilename)
    {
        File::assertFile($pFilename);

        // Check if gzlib functions are available
        if (!function_exists('gzread')) {
            throw new Exception('gzlib library is not enabled');
        }

        // Read signature data (first 3 bytes)
        $fh = fopen($pFilename, 'r');
        $data = fread($fh, 2);
        fclose($fh);

        return $data == chr(0x1F) . chr(0x8B);
    }
Can the current IReader read the file?

@param string $pFilename

@throws Exception

@return bool