def _is_mobi(file_bytes: bytes) -> bool:
	"""
	Decide if a file is a MOBI/AZW3 file.
	From ./se/vendor/kindleunpack/mobi_sectioner.py lines 49-53
	"""

	return file_bytes[:78][0x3C:0x3C+8] in (b"BOOKMOBI", b"TEXtREAd")