Php and yaml files in copied theme

If I create a new theme, which is copied from another (learn2 in this case) and change the name of the theme folder to ‘mytheme’ but forget to rename learn2.php and learn2.yaml to mytheme.php and mytheme.yaml would this cause problems and have significant impact on performance?

The yaml and php files must have the same name as the folder or they are not recognized.

Makes sense but what impact might this have?

There’s no performance issue, they are loaded as needed.