[PF]Feat for Ignoring Opposition Schools?

[RndmNumGen]

Somebody mentioned that there was a feat in Pathfinder that allowed wizards to cast spells from their opposition schools normally, without needing to expend double spell slots. They sort of disappeared after that though, and I haven't been able to locate that feat on the SRD anywhere. Does somebody know what it is?

[Blisstake]

In Ultimate Magic, a wizard can replace a feat or bonus feat with an arcane discovery. At ninth level, you may select opposition research, which allows you to cast from one of your opposed schools normally.

[RndmNumGen]

Okay, thanks.