The two Ensighten
.rnc one-way pixels that you might have notice on your site are the TagAuditBeacon.rnc and Perf.rnc used to power your standard Manage Tag Error report and Performance report, respectively.
The "rnc" source type stands for "return no content".
The beacons collect PII-free information about your traffic so generate and provide you key information about your tags delivered through Manage on your site. The beacons do not effect your existing Bootstrap.
Contact Ensighten Support if you do not have your beacons turned on and would like us to power them up.