Windows 11 has built-in support for the RAR format
The company used the open-source libarchive project, which added support for the following formats to the operating system: .tar, .tar.gz, .tar.bz2, .tar.zst, .tar.xz, .tgz, .tbz2, .tzst, .txz, .rar, .7z.
However, if the archive files are password protected, users will still need third-party programs to access them.
KB5031455 is an optional update, and in order to install the new build, users will need to find it in the Windows Update list of updates. If testing is successful, the new functionality will be available in stable builds of the OS in the near future.