Hi and thanks for reaching out. My name is Bernard. I'm a Microsoft Windows expert and a Microsoft Windows fan like you. I'll be happy to help you out today.
Yes it is safe as that are previously downloaded system files it is likely a cache and temp files of Windows Store apps and more.
You may also refer to this link: https://support.microsoft.com/en-us/windows/win...
You may also check it here: https://www.howtogeek.com/266337/what-should-i-...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Let me know how does it goes and I hope that helps.
Bernard
Independent Advisor