Experimental packages are unsupported, may not be part of the roadmap, and can be deprecated without release. We still welcome feedback from early adopters on these cutting-edge, exploratory tools. Use the Add package by name option from the additional menu (+) in the Package Manager window to add them.
The new package lifecycle
Starting with Unity 2021.1, we introduced new nomenclature to provide better guidance on a package’s readiness, progress, expected support level, and Unity’s long-term commitment.