Earlier quoted context omitted.
5 years at Google is forever, and it's not uncommon at all for people to jump around projects at the company. It's also a full year beyond what's necessary to vest. Really silly way to write that.
European here - what's it mean to vest shares? It sounds like some sort of stock options became unlocked? I haven't heard of this thing before, just of stocks being part of salary for small startups that don't have actual money to pay you (or at least, that's what I've heard warnings for on HN).
This helps them reduce compensation during hard times. Salaries are very sticky; it’s hard to cut salaries. So they offer RSU comp because it’s tied to stock price. When the company is doing poorly, they can pay less. But it also lets the pay high compensation and retain long term talent.