Adwords conversion tracking code.
https://support.google.com/adwords/answer/6095821#get_tag
Analytics and Tracking · Advertiser Tracking
Get access to data on 432,186 websites that are Google AdWords Conversion Customers. We know of 240,650 live websites using Google AdWords Conversion and an additional 191,536 sites that used Google AdWords Conversion historically and 123,672 websites in the United States.
Get a list of 432,186 websites using Google AdWords Conversion which includes location information, hosting data, contact details, 645,655 currently live websites which includes 405,005 domains that redirect to sites in the list. 191,536 sites that used this technology previously and 123,672 websites in the United States currently using Google AdWords Conversion.