This version of Unity is unsupported.
MockHMD XR Plugin
Package Validation Suite

Package Development

com.unity.upm.develop preview 

Description

Installs the UPM package development extension. Author new UPM packages and manage them with the new In-Development mode in the Package Manager UI. Publish your packages to a local file, scoped registry or Asset Store

Version information

Experimental for Unity

These package versions are considered unstable for Unity version 2019.3:

Documentation location: Versions available:
com.unity.upm.develop@0.1 0.1.2-preview
0.1.1-preview
MockHMD XR Plugin
Package Validation Suite