What does system cleaning' mean?

The program stores various files on the hard disk when performing various tasks.
The majority of the time, these files have no effect on the system's operation.
It actually slows down the machine by taking up space. Cleaning is a technique for keeping the system from losing speed.
The following are the files that relate to system cleaning:

• Downloaded Program Files
•  Recycle Bin
•  Temporary Files
• Temporary Internet Files
•  Offline Webpage
•  Setup Log Files
•  Thumbnails