It's a board-to-board interconnect with a 0.100" (2.54mm) pitch on both rows and between rows, making it a drop-in fit for standard 0.100" grid prototyping and production boards. The 30.0 µin (0.76 µm) gold or GXT™ plating on the mating surface provides the cycle life for repeated connect and disconnect in test fixtures or field-serviceable assemblies, while the UL 94 V-0 black thermoplastic housing meets the flammability rating required for equipment inside an enclosure. All 58 positions are loaded, so the pinout matches the position count one-to-one.
The 0.100" (2.54mm) pitch is the de facto standard for 0.1" grid perfboard and many legacy bus architectures. The 58 positions in two rows give a 29-per-side layout, which means the board footprint occupies 29 × 0.100" = 2.900" along the row, plus the right-angle tail overhang. The 0.095" (2.41mm) post length is a short solder tail — it's meant for standard 0.062" PCBs, not thick backplanes. Tin plating would be cheaper but would wear faster under repeated connect cycles.