[Vinnl]

Importantly, though, that inbox is not an email inbox. This is what the process might look like (i.e. I've been through this):

1. You can an email in your regular email stating that there is a new message in your Berichteninbox. (No clickable link, presumably to avoid phishing.)

2. You go to mijn.overheid.nl to access your Berichteninbox. You sign in with DigID.

3. You open the mentioned message, which says a PDF with the actual letter is attached.

4. You open the PDF.

5. The PDF says you'll be able to file your tax returns a month from now.

[teekert]

Yes, that is the process, it's pretty involved indeed, biometric auth and apps opening other apps on mobile makes it bearable. But indeed, if you look at the number of successive actions in such a seemingly simple thing, it's quite a lot.

BTW, if said PDF contains an iDeal payment link, you can switch to yet another app (your banking app) and back (probably via website in between) and immediately pay things. Which is nice, but again watching over the shoulder of someone going through these actions it may seem that the phone is going crazy switching between apps :)