Microsoft has shared details on Known Issue Rollback (KIR), a Windows 10 capability used to revert buggy non-security fixes delivered through Windows Update. KIR allows Microsoft to revert single and targeted bug fixes once critical regressions are detected. Microsoft has been using KIR to rollback computers affected by problematic bug fixes to a working state since late 2019. A fully working version of KIR was introduced in Windows 10 2004 when all the components began working together as a functionally complete system, Microsoft said.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-windows-10-known-issue-rollback-auto-fixes-update-bugs/