"Negative harmony" is a term from the theorist Ernst Levy and his book A Theory of Harmony. Here's what's actually happening:
Let's say you're in C. The idea is that the "axis" of C is the perfect fifth C/G. So, when you have a G7, you're actually inverting it around this C/G axis. Or, put another way, the halfway point between C and G is right between E and E♭, so you're actually rotating it around that point.
Like the exact opposite of the first kiss we shared, that meant nothing to me. Inverting? Rotating? Whatever's going on, it made the song sound like a 90's indy rock cover. And you know how I feel about 90's indy rock covers. "Best songs to make love to." I stand by that. Or should I say, I lay by that. HIYO, I'm a stupid idiot.
Keep going for this negative harmony cover, as well as a variety of others for reference, including Toto's 'Africa', Led Zeppelin's 'Stairway To Heaven', Radiohead's 'Karma Police', the Pixies' 'Where Is My Mind', No Doubt's 'Don't Speak' (that one is fun), Oasis's 'Wonderwall', and Nirvana's 'Smells Like Teen Spirit'.
Thanks to Jeffrey S, who actually tried to explain negative harmonies to me but, just like a 'you must be this tall to ride this ride' sign at an amusement park, it was way over my head.