Resetting Themes Folder to Default

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Short answer: No, WordPress does not manage your theme directory, and there is no reset function.

There are two important points you should learn from that experience:

  1. Always test new software (themes and plugins) in a local installation. Do not just upload something you have not tested before.

  2. You could manage the directory or your whole installation with a version control software like Git or Mercurial. This way, you could reset the directory content to an earlier state, it would take just one command in a terminal. And some time to learn these tools, of course.