Explanation
Default Solution. This is a special solution that contains all components in the system. The default solution is useful for discovering all the components and configurations in your system.
Why you shouldn't use the default solutions to manage customizations
There are a few reasons why you shouldn't create apps and make customizations in either of the default solutions:
* The default solution can't be exported; therefore, you can't distribute the default solution to another environment.
The default solution contains all components and customizations from all solutions in the environment.
By default, all enabled users can create apps and customize components in the Common Data Services Default Solution.
It's difficult to locate or identify the customizations you've made in the environment by using either default solution.
When you use either default solution to create components, you'll also use the default publisher assigned to the solution. This often results in the wrong publisher prefix being applied to some components.
Reference:
https://docs.microsoft.com/en-us/power-platform/alm/use-solutions-for-your-customizations