Google weblight is a google service, which shows the compressed view of the webpages listed in the search results when a slow network is detected. It removes websites default styles and js files, So user can view the webpage much quicker. But it can be disabled by setting cache control header to no transform.
Google ranks ( between 0 to 10 ) every page of your website. Mostly these ranks depends on number of back links to that page. Highly ranked pages will get higher position in the search results. Find out how to retrieve Google pagerank for given url using php