Since the dawn of the world wide web in the mid-90s, there hasn't been an standard way of identifying *who did what* as far as building a web site is concerned.
Some ad-hoc techniques are still in play today, such as the designer or developer adding a small image in the footer of a web site, typically with some 'built by' text. Another old school technique is for developers to add some commented-out HTML code to the header of the web site, which is only visible when users view the source code.
Both techniques have SEO ramifications, as well as aesthetic and commercial overheads. More importantly, neither method goes any way to accurately describe who did what - it's more commonly just an ad for the person who was last able to insert their stamp into the original web site.
