what's going on ?

Just Katy stanning for an amazing track

Probably not. She probably just saw Katy's name in the title and decided to run in per usual.

Is she in the clear yet?

actually, yes very much so. Look at the people she's brought on tour; HAIM, Tove Lo, Kacey Musgraves, Charli XCX, Capital Cities. These are all singers she found before they were popular, and now just a few months/years later all of them have huge hits and/or acclaim. Meanwhile Taylor's bringing some Vine guy on tour.

Those artists have hits and tight indie fanbases so people can go to her shows for the opening act alone.

Taylor is shining a spotlight on the newbies of the industry

Meanwhile, Taylor is bringing Vance Joy (who is a fantastic singer/songwriter on the brink of having a big breakthrough) and Shawn Mendes, who is a young, extremely talented singer. Calling him "some vine guy" makes it painfully obvious how you're trying to twist it.

What's ootw? A show? A song?

Out Of This World

None of them had hits when they signed the tour contract. Katy giving hit power to indie acts/future pop girls
I love Vance Joy. Shawn Mendes is nothing special