LAYOUT FILES: AVR-ISP adapter: 6pin (2.54mm) --> 6pin pogo-pins (1.27mm).
When your boards get smaller and smaller and it gets harder and harder to find a spot for the programming connector.
Pogo-pin type: "P50 - E2", 0.68mm body diameter, 0.9mm head diameter.
PCB thickness: 0.6mm !
Before having PC-boards made, please make sure you know about your manufacturer's peculiarities! Especially drill-sizes and their tolerances may vary too much and give you trouble.