I can't understand what you're talking about.

Konami has clearly mentioned that:

1: Players whose max level cap is 30 or below (means scouted players) will have their level set to 30 in PES 2019.

2: Players whose max level cap is above 30 (means players we obtained from Agents/Box draws) will have their level maxed out, their final lvl is determined by Age and other factors.

So there is no concept of 31 lvl player or use a limit breaker etc.

For example, if you've a non-scouted version of Mbappe, you'll get Mbappe full trained to lvl 68 in PES 2019.

If you've scouted version of Mbappe, you'll get Mbappe trained to lvl 30.

The only thing we don't know yet is that whether we'll be able to train scouted version beyond lvl 30.