Thanks Eugene!
As you wrote, the difference is the thickness of drive links in chain. And two file kits have different part numbers of combi gauges.
If the two file kits can be applied identically, I couldn't understand why Husqvarna made those two kinds of file kits.
That annoys me a lot!
Thanks! According to Husqvarna web page, H30 Pixel chain uses only H30 Pixel File kit instead of H25 File kit. All other .325 pitch / .053 gauge chains use H25 type combi gauge. I am aware of the 0.2mm difference of drive links. That annoys me a lot!