Microsoft routinely conducts experiments with Windows 10 users to determine if a feature is commonly used, if a change in a feature makes it more useful, or to introduce features to a small test population. Some users find these experiments a breach of privacy and wish to disable them by creating the ‘AllowExperimentation’ value and setting it to ‘0’ under the following Registry key. Microsoft recently used the Windows 10 Known Issue Rollback feature to fix performance problems while playing games, users learned that disabling experiments prevents the KIR fixes from being installed.
Source: https://www.bleepingcomputer.com/news/microsoft/disabling-windows-10-experiments-blocks-known-issue-rollback-fixes/