Adwords conversion tracking code.
https://support.google.com/adwords/answer/6095821#get_tag
Analytics and Tracking · Advertiser Tracking
Get access to data on 610,371 websites that are Google AdWords Conversion Customers. We know of 387,986 live websites using Google AdWords Conversion and an additional 222,385 sites that used Google AdWords Conversion historically and 196,394 websites in the United States.
Get a list of 610,371 websites using Google AdWords Conversion which includes location information, hosting data, contact details, 387,986 currently live websites and an additional 590,788 domains that redirect to sites in this list. 222,385 sites that used this technology previously and 196,394 websites in the United States currently using Google AdWords Conversion.