Can you help me explain the code above? some of my younger siblings found it in The Help, and some of them couldn't find it.

Can you help me explain the following code: some of the code I found in help, and some cannot find the header (& quot; Content-type: application/octet-stream & quot;); header (& quot; Accept-ranges: bytes & quot;); header (& quot; A can help you explain, some of the following code can be found in the help and some cannot be found.
Header ("Content-type: application/octet-stream ");
Header ("Accept-ranges: bytes ");
Header ("Accept-length:". filesize ($ path ));
Header ("Content-Disposition: attachment; filename =". $ filename );

------ Solution --------------------
This is the header information for generating the Download box.
------ Solution --------------------
That is, tell the browser to start downloading the file.