What does that even mean? The devs only targeting Xbox One don't even need to worry about it, because the software arch will take care of it. You can play Xbox One games on the Xbox One X without even worrying about a 'boost mode' or anything like that which frankly should've been on by default on the Pro, not a post release consideration.
The Xbox One( and S) are a physically different architecture that developers need to specifically optimize for to take advantage of. The XBox X uses similar architecture as PS4/PS4 Pro.
The issue isnt which arch is better. Its the fact that Sony made the PS4 Pro a superset of PS4. For any multi-player game, devs can without any effort have everyone on the same exact performance profile/footing.
MS had to drop the design they had for Xbox One because they could not scale it. They thought the Xbox One was it for the next 5-7 years. The original design was a compromise purely due to having similar budget as PS4 but spent a bunch of it on non-gaming features so they had to make cuts on the gaming side. The DDR3+big cache(that you need to specifically program for to fully utilize) instead of GDDR5, less GPU "CU"s,... The Xbox S was the best they could do with original design's handicaps. The X chooses the more sane design when gaming is much higher priority than whatever number 2 priority is.
Unlike the PS4 Pro where it literally can be a PS4 by not utilizing extra GPU CUs and lower clock rates on GPU/CPU, the Xbox One/S and Xbox X cant do that. Its different hardware. They just have to guesstimate that they are getting similar performance. [edit: my point is from reading TR's excellent reviews with 99th percentile, that average fps means nothing, and in multi-player its the little dips that matter]
There are a lot of implications besides what i say by going with path MS choose. Not saying the Xbox X is a bad console at all. But talking about what it means for entire platform. This whole mess is because those compromises made the Xbox One not what someone expected of a 1080p console. And the easy synergy between PS4(perfectly viable 1080p console) and PS4 Pro has to count for something.
And im not being unfair to Xbox One(S), they did not spend a significant portion of budget for gaming hardware.