Perhaps you are misinformed but there are no mempool config options that are being removed from Core.
Discussion
heads-up: we looked for a lightning address on your profile but could not find one... u can get a free one at https://rizful.com ... and then reply back to this comment so we can zap you.
This appears correct -- because they never made it user configurable in the first place. I'd seen the config option proposed, but didn't realize it was never there in the first place, only that it was rejected.
So yes, my characterization of the order of events was flawed. The end result though is still that Knots provides options that Core refuses to.
OPreturn is configurable in Core. What do you believe isnt configurable?
Ahh, they haven't removed it yet -- but it's marked as deprecated, and I'm seeing that at least the suggestion of this is that it means it will be removed in the future (though of course it's code and anything can change).
The option here is datacarriersize.