Ironcially:
they've been emailing people suggesting this security-check. I initially marked the email as spam cause
it looked suspiciously like a pishing mail:
Click this link [to a completely unknown destination with a very long url] - and be sure and have your password ready...
Ironic bacause they were promoting "Safer Internet Day":
remember to always have your password ready - no matter who asks (or where that link leads) :-)