I find this new text far better than what had been defined recently.
For the last few years the rule was written:
Baggage regulations - the piece system applies to passengers travelling on a oneworld Explorer fare.
Now it is:
Baggage regulations
Two free pieces of 23 kilos each shall be permitted. Additional allowances may apply. Refer to individual carrier websites.
As posted, any allowance above that 2 x 23Kg would be generally segment based and a function of your travel class, your status (with the operating carrier) and any other factor as denoted by the operating carrier.
Oh, and by the way - it still is designating a "Piece System".