Quoted from the email (received from Google Play, 7 hours ago):
* If you are an individual developer declared as a trader, provide and verify a public phone number. Please be aware that your phone number and address will be displayed publicly on Google Play.
* You’re typically considered a trader under European Economic Area (EEA) and United Kingdom (UK) laws if you engage in commercial activities, including when you earn revenue from your apps (such as paid downloads, in-app products, subscriptions, or ads).
* If you don't complete your trader status declaration by the deadline, you won't be able to submit app updates, and your developer profile and all apps will be removed from Google Play globally.
* You must declare your trader status in Play Console, regardless of where you’re located.