Why is there no Entities package in 2020 version of Unity?

Question

Unity

Hello.

Installed Unity 2020.1.8f1, created a new project - I don't see the Entities package for ECS in the package manager. Enabled displaying preview versions of packages.
Installed Unity 2019.4.12f1. Similarly, I created a project, I display preview packages and there are Entites.

Why is this package not in the new version of the unit? Why only in LTS?

Thank you.

Answer 1

https://blogs.unity3d.com/2020/06/24/package-manag...
Apparently the package is experimental and does not appear in the package manager. They write that it is possible to add handles by editing the project manifest.