WordPress 5.3 “Kirk” was released in 12th November 2019.
I noticed some problems with the existing API reference so decided to completely rebuild it, for every subdomain, starting with core.wp-a2z.org, then moving on to the other domains.
I ran it yesterday on core and checked it today – 14th November.
It’s not looking good. Not at all!
Sorry, I’ll try again. I think it might have been a problem with PHP 7.3
Meanwhile, why not have a look at the 74 blocks delivered by WordPress core.