The Net Yaroze is essentially a developer kit sold to consumers. By connecting the console to a personal computer the user could compile code for a program to run on the PlayStation.
Bundled Accessories
Adapted from Wikipedia:
1 Net Yaroze PlayStation console (black matte texture)
2 PlayStation controllers (black matte texture)
1 AC power cord
1 AV cable
1 Net Yaroze boot disc (a greenish PlayStation CD-ROM)
1 Net Yaroze software development disc (A CD-ROM containing development tools for PC)
1 Access Card (a black memory card-like dongle, required for booting in remote-controlled mode), with sticker
1 Communications Cable (a special serial cable used to link the console and the computer over a serial communication)
1 "Start Up Guide" manual
1 "Library Reference" manual
1 "User Guide" manual
Trivia
[Trivia taken from Wikipedia page]
Yaroze means "Let's do it together"
Boots in NTSC mode. However the console is region free
Compatable with IBM-PC, Macintosh or NEC PC-9801
Sold through mail order. Also provided to some Japanese universities