Is there a website with up-to-date info on border checks in the EU due to Covid-19?

I will soon travel from France to Austria via Switzerland, and am unsure about the status of border controls. As a UK citizen, I am in principle permitted to travel to Austria (at the current date) as long as I can prove that my journey is "essential" and that I recently tested negative for coronavirus, unless I have a residency permit and am travelling via a ‘safe’ country.

But I am curious about whether anyone will anyone actually check my passport/details if I am traveling from one ‘safe’ Schengen country (Switzerland) to another (Austria) via night train, or whether all passengers must present proof of residency or other documentation. I did not have to give my nationality or passport number to the train company when making the bookings.

So my question: is there a site that I can refer to for up-to-date information about which borders within the EU (specifically the Schengen area) are subject to checks due to Covid-19? E.g. UK-France is possible subject to some paperwork, France-Switzerland appears to be fine, and Switzerland-Austria depends on residency status.