Stumbled onto https://www.kernelconfig.io from npub1ekly7ytnxrcn08zx0h29ztdhctpgnhgpxmhpul0z078h9d0t40msk5n5jn (npub1ekl…n5jn):
From a quick look it seems to be LKDDb (#Linux #Kernel Driver DataBase) with a nicer Web UI and a few other differences -- some of which might be nice to have.
The two screenshots below compare https://www.kernelconfig.io/CONFIG_PREEMPT_RT and https://cateee.net/lkddb/web-lkddb/PREEMPT_RT.html