This module allows other modules to provide configurations that override default config provided by other modules, including core and contrib. It is intended for use by distribution/installation profile maintainers who want something in Drupal 8/9 that's closer to what was possible in Drupal 7 with the Features module -- the ability to break up config into logical sub-modules rather than everything having to be in the installation profile.
This allows you to see not only the total execution time of the Drupal Request, but also detailed information about internal processes like time spent on preparing the Request, SQL queries, etc.