I have seen it claimed that Paul 6 "abolished" the major order of subdeacon and all of the minor orders (acolyte, exorcist (huh? aren't there still novus ordo exorcists?), lector, and porter) in his docuмent Pontificalis Romani.

Well i read it and there was no mention of any abolishing of these things; there was no mention of them at all.

Was the abolishing by way of not mentioning them or de facto, by simply not using them anymore? Or is there somewhere any docuмent or something which clearly says these orders are now out?

This is of course very significant because of the following:

"...from the very beginning of the Church the names of the following orders and the duties proper to each one are known to have been in use, namely those of the subdeacon, acolyte, exorcist, rector, and porter, though not of equal rank; for the subdiaconate is classed among the major orders by the Fathers and the sacred Councils, in which we also read very frequently of other inferior orders" (Council of Trent, Session 23, Ch. 2; Denz. 958)

"If anyone says that besides the priesthood there are in the Catholic Church no other orders, both major and minor, by which as by certain grades, there is an advance to the priesthood: let him be anathema" (Council of Trent, Session 23, Canon 2; Denz. 962)

I see.

Paul VI did not abolish all the minor orders (which renamed "ministries"); see his Ministeria Quaedam (15 Aug. 1972), in which he retains the reader and acolyte but abolishes the others, porter & exorcist, because apparently those aren't "adapted to contemporary needs"!