Postgres 16 does not seem to have any extensions installed, yet:  
https://dbfiddle.uk/5xBOE_of

We did have the most important ones in Postgres 15:  
https://dbfiddle.uk/ZvVRGTUS

I later found (to my surprise) that I am allowed to install extensions myself in pg 16.
And I even have superuser privileges now! Example:  
https://dbfiddle.uk/Iu3_NYjM

Is that all as intended?
I suspect most people won't pick up on the changes between pg 15 & pg 16 immediately. The extensions are pretty important. Do you think we could have them pre-installed in Postgres 16?  

Still loving your site!