This is a V-USB development board meant to fit inside a metal (possibly scavenged) USB type-A shroud.

The board will probably need to be sanded down on the long sides to fit well. The thickness of the board and the shroud should be just about perfect to provide a nice, solid USB connection. The bottom layer also exposes a VBUS trace that should be insulated from the shroud with kapton tape, solder-mask pen, etc. After all that, carefully superglue that lil' sucker inside the shroud. If you don’t want the ISP header, feel free to cut along the advertised line. The board /should/ be near flush with the edge of many shrouds.

Ideally, this design would be software compatible with the adafruit trinket 5v. D+ and D- are swapped from the adafruit schematic, so you’ll have to alter the code. It doesn’t support a regulator, have a reset button, or any other schnazzy bells and whistles, so YMMV.