The use of "path" attribute in "data-sly-resource" :
When a component with the above snippet is included in a page, we would see a parsys being displayed and when we add any components within the parsys placeholder, behind the scene in the CRXDE, we would see the components available in the node hierarchy like below.
Let's say the page path is /content/xyx/abc.html
In CRXDE, /content/xyx/abc/jcr:content/FirstDivHeader/componentname(that you would have included in that parsys)
In brief, it is part of the path with respect to the page where this snippet/component is being used.