What this 40-position header is built for
The 5-104068-4 is a vertical through-hole header from TE's AMPMODU System 50 series, packing 40 male pin contacts in two rows at a 0.050" (1.27 mm) pitch.
At 0.050" pitch, the per-contact current rating is not specified in the record, but in the AMPMODU System 50 family, the limiting factor is the contact cross-section and the 30 VAC voltage rating. For signal-level currents (sub-1 A per contact), the 40-position density is practical; for higher currents, derate based on the total bundle and ambient temperature. The thermoplastic insulation material (black) holds up through wave solder and cleaning cycles.
Compared to the 1-1871673-2 (4 positions, 0.098" pitch, right-angle, 4-wall shroud, tin mating contacts), the 5-104068-4 offers a much higher circuit count (40 vs 4) at a tighter pitch (1.27 mm vs 2.50 mm) and with gold-plated mating contacts for better cycle life. The right-angle 1-1871673-2 is better for board-edge cable exits; the vertical 5-104068-4 suits top-entry mezzanine or wire-to-board connections. Against the 1318699-3 (12 positions, 0.165" pitch, 4-row, 5 A rated, gold flash), the 5-104068-4 has more positions and a finer pitch but no current rating specified — the 1318699-3 is the better choice if you need 5 A per contact and a 4-row layout. The 5-104068-4's 30 µinch gold is thicker than the 3 µinch flash on the 1318699-3, so it will withstand more mating cycles.