Which and how explicit $W$ current involved process violates CP? (given we knew the fact CKM matrix complex angle violates the CP)

We know that the 3 generations of quarks have a 3 by 3 CKM matrix which contains a complex angle that cannot be rotated away. And this CKM matrix complex angle violates the CP, because it has a complex coupling in the $W$-current Lagrangian.

In Peskin QFT p.725, it says:

The CKM phase contribute CP violation only:

1. through weak interaction loop corrections.
2. complicated exclusive decay process.

Question

So which explicit $W$ current involved process violates CP via this CKM matrix complex angle ? Which mesons ($K$?) and decays to what? Can we state precisely how do the scattering or decay rates are different from a process and the CP conjugate process within this Standard Model CKM matrix complex angle violates the CP?

Merci!

refs:

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possible useful but not enough explicit process to show CP violation: