This packaged product is a **Quick Solder Board (QSB) kit for "Phat" (original/fat) Xbox 360 consoles**, specifically the Team Xecuter PHAT QSB V3 (or a similar/compatible version) used for NAND-X, JR Programmer, and CoolRunner installations.
It's a modding accessory for Xbox 360 homebrew/hacking modifications (like RGH/R-JTAG glitches to run unsigned code, backups, or custom firmware). The kit typically includes small PCBs that solder onto the motherboard for easier connections when reading/writing the NAND flash, installing glitch chips, or programming.
The black backing is anti-static foam for protection, the white foam pad cushions the delicate boards, and the green "QSB PHAT" label identifies it (common in third-party or clone kits sold on sites like eBay/AliExpress).
These are popular in the retro console modding community for bypassing dashboard restrictions on older Xbox 360 phat models (e.g., Zephyr, Falcon, Jasper)
I found this going through some drawers, and I no longer have consoles to tinker with, so if anyone out there is looking for one of these, I've got you.