you can make that, but you should try to understand how hard it is. To do it, you add a specific string of text to every
html/php/asp etc. file, and then you need to build a custom infrastructure to handle all of the requests for manifest files w/ responses customized per user. Also, the language used is completely unsupported in most editors, and it involves a ton of serverside hacking. They could
do it, but it would be extremely difficult.