We removed the Test jQuery Updates plugin from mu-plugins.
#test-jquery-updates
Updated Test jQuery Updates to the latest upstream version to bring in support for WordPress 5.7 and various minor improvements / bugfixes.
Note We are on 2.0.x because have modified the plugin. The current latest 2.0 release doesn’t operate as expected on read-only file systems due to capability check changes. An issue have been opened here.