In every release, the PostgreSQL Global Development Group introduces a set of new features that span from performance improvements to configuration management to adherence to the SQL standard and so on. PostgreSQL 13 follows its own path and introduces a rich set of new features; many of them are "under the hood" and so you will not perceive them during day-to-day database usage, but they are really important for the cluster to work more efficiently.
This section provides you with a categorization of the main features introduced with the upcoming PostgreSQL 13 release, which at the time of writing is still in beta 2 release, so it's stable enough for usage and testing but not yet production-ready. As you can imagine, it is not possible to explain (or even worth explaining) every single feature in detail, so you will just get an at-a-glance idea of the main changes. The changes are presented in no particular order.