[bassdart]

They ask for your current mobile number -- at least in germany and without any anonymization beside standard browser configuration like e.g. uBlock Origin. So it's simply to suck in numbers. I have not tried if they ask for more data after giving a phone number and so I can't log into two google/youtube test accounts any more since a few years.

[jacekm]

The phone number is the last step, at least it was for me. I had luck with virtual phone numbers, not the freely available ones, but paid apps like e.g. Vyke.

[flangola7]

So what happens after you use Chrome and type in your number?