AR-Menu/Library/PackageCache/com.unity.collab-proxy@c854d1f7d97f/Editor/_Deprecated/README.md

Deprecated public classes that we need to keep until we change the major version of the package to 3.x. Removing any public API in a minor version is forbidden.

The issue is that updating the major version of a default package is forbidden in a stable Unity Editor version, so we cannot do it during the lifetime of Unity 6.x.