We are unsure if Riot Russia leaked Zeris abilities ahead of time, or if there was a mixup with the timezones, or something similar. The cat is out of the bag, though, and here is the rundown of her abilities.
From birth, Zeri had a unique relationship with electricity. Each giggle caught a spark—each cry, a shock. Magic wasn’t rare in Zaun, but Zeri’s electric charm was. It charged with her emotions, sometimes grounded, sometimes building too fierce and fiery. By her teenage years, her neighbors knew she was more likely the cause of power outages than a broken circuit. Life in Zaun was beautiful chaos, her grandma would say, and Zeri embodied that all too well.
After a terrible accident caused by the negligence of a chem baron, Zeri starts to take matters into her own hands and fight for her people.
Her in-game abilities have just been teased, but not fully revealed. Even so, we can make an educated guess as to what they are.
Her auto attacks, with some passive clause, as is expected of electricity, pierce the enemy champions, not unlike Twitches ultimate, and will likely deal AoE damage to those standing behind the champions Zeri is attacking.
Her core ability seems to be her dash. As the trailer has shown us, she can dash over walls after taking time to charge up, as well. It is unlikely that this is a separate ability, but rather that her dash works like Pyke's hook or Pantheon's spear, with charge time for long-range, and a tap for a short-range dash.
One of her abilities gives Zeri a shield, and possibly some movement speed, while her ultimate ability discharges her electricity around her in a circle, and looks as if Neeko's and Blitzcrank's ultimate were made into one.