Create a schematic of files used in a website

We have been modifying, changing, adding to our primary website for 16 years and we have many redundant files on our server. Basically its a mess and we need to cull all the unused files. The job is to start at "[login to view URL]" and review all our html code to see what files are called or linked to in the website from this we will have schematic and a list of files in use. All the code is in PHP. We will provide FTP access and would want you to download each file as it is is referenced. WE DO NOT WANT ANY CHANGES MADE!