{MAGIC(4bytes)}
{VERSION(3bytes)[maj,min,rev]}
{ORIG_FILE_SIZE(8bytes)}                -- Was 4bytes before 0.8.38
{NUM_BLOCKS(4bytes)}
{BLOCK_SIZE_UNCOMPR(4bytes)},
{OPTIONS(1byte)}
{EXTD_SIZE(4bytes)}
(EXTD):{
	{OPTION(1byte)}
	{OPTION_SIZE(2bytes)}
	{OPTION_VAL(OPTION_SIZE bytes)}
}
(BLOCK):{
	{ALGO(1byte)}
	{BLOCK_SIZE([BYTESIZE(BLOCK_SIZE)] bytes)}
	{BLOCK(BLOCK_SIZE bytes)}
}