What is the relevant impeachment evidence that must be disclosed to the defense?

"[T]he existence of a plea agreement is relevant impeachment evidence that must be disclosed to the defense because it bears on the witness's credibility. [Citation.] . . . '[W]hen an accomplice testifies for the prosecution, full disclosure of any agreement affecting the witness is required to ensure that the jury has a complete picture of the factors affecting the witness's credibility.' " (People v. Fauber (1992) 2 Cal.4th 792, 821 (Fauber); People v. Bonilla (2007) 41 Cal.4th 313, 337.)