Rear axle sizing for wheel set, compatible with both 142mm thru axle and 135mm quick release?
135 QR and 142x12 thru axle are two wholly different standards with no intrinsic cross compatibility.
They both locate the cassette in the same place relative to the frame centerline, or in other words they give the same chainline. 142x12 is essentially the iteration of a thru axle rear end that didn't change anything else about the parts that would play nice on the rest of the bike, coming out of the long period where 135 was the only game in town for a disc bike.
All that said, it's extremely common for aftermarket 142x12 wheelsets and hubs to have 135 QR adapter endcaps either included or available. These are all proprietary to the hubs they're made to go in. It's pretty common for them to be included and I believe that is the case for the DT wheel in question.
Whether the freehub body is XDR or XD or HG or Microspline or whatever is immaterial to the frame the hub is going in. All that matters is either endcap availability or native compatibility with the standard the frame is made to.