Update HTML File

Can someone tell me the purpose of the “update html file” button in FTP setup/web files? Upper right hand corner.
Just wondering,
Jim

Can someone tell me the purpose of the "update html file" button in FTP setup/web files? Upper right hand corner. Just wondering, Jim
I use that button, when I make a change in WD, to see how the change may affect my web page without uploading the web page to my ISP. I then click on