The file extension is just three little letters after a dot (.)

If you are lucky, some program on your computer with a file association will understand the specific file structure and do something meaningful...

BIN = Audio format (short ints,no header)
BIN = Binary file
BIN = MacBinary archive format often used on Macintosh
BIN = machine language
BIN = Micrografx Designer 7 Project Image
BIN = Mime: application/mac-binary
BIN = Mime: application/macbinary
BIN = Mime: application/octet-stream
BIN = Mime: application/x-binary
BIN = Mime: application/x-macbinary
BIN = SGI Powerflip
...
RAR = Mime: application/rar
RAR = RAR-compressed archive
...
ISO = 9660 = iso 9660 cd-rom file system format
ISO = CALS ISO 8613 : Bitmap graphics
ISO = Easy CD Creator CD image file
ISO = International Standards Organization : ISO-9660 table
ISO = ISO Buster File
...
ACE = Aces200 image format
ACE = Archive
...
etc...

__________________
Geo here... <small>antique computer enthusiast
Mac Powerbook G3/500MHz=<i>Pismo</i> :: 384MB ram; 80GB hdd; <b>MacOS 9.2.2</b>
Compaq Presario 5360 :: 450MHz AMD Athlon, 192MB ram; 120GB hdd; <b>Win2k PRO SP4</b>
ISP :: <u><b>SBC</b>-Yahoo!-DSL</u>; 164KB/sec DL; 50KB/sec UL; <u><b>2Wire</b> <i>DSL modem / Wi-Fi / NAT firewall</i></u>
PtoP :: LimeWire 4.8.1 <b>PRO</b> || Shareaza 2.1 <i>for BitTorrents, mostly</i> || but not concurrently! <i>
This is an INTEL-free, pre-Y2K CPU, recycled-computer environment! </i>