Don't mean to necro a thread, but I thought someone may find this useful.
I tapped into that connector to create a 3 pin JST for a 5v addressable RGB strip.
From the bottom picture (clip on top of the 2.54 JST four pin connector) Left to Right:
1. rgb data 2. 5v 3. common ground 4. 12v
That end, in JST, is called the FEMALE connector, as that is driven by the connector (and not the pins).
So I re-pinned a four pin (removing the 12v line) on a male connector, then soldered the lines: 5v data and ground, in the order for a female three pin JST 2.54 pitch, which plugged directly into my LED strip.
My case came with three argb fans on that connector (from Skytech) with the same custom four pin JST. Full on 12v fans with no control. Moved two exhaust out (and replaced with MB header driven fans) and put a 47 ohm 1 watt resistor in the 12v line to slow the rear exhaust down a bit.
Love my H200 TG, but the wiring is confusing with no explanation.