Another series of cards described certain immigration offenses and related federal charges: misuse of a passport, fraud or misuse of a visa, and fleeing from a checkpoint. Cards about voluntary return to countries outside the US, expedited removal, and warrant of removal described forms that needed to be filled out and then offered a reminder about a checklist on something called an “agents Resources Page” to ensure “accuracy of all above.”

“We take reports of sensitive or inappropriate content seriously and act promptly when content is found to violate our policies,” a Quizlet spokesperson wrote in a statement. “We encourage anyone who encounters concerning material to report it directly from the flashcard set, class, or profile page, or to contact us so we can review and take appropriate action.”

Other cards offered detailed information about the Kingsville workforce’s 1,932-square-mile area of responsibility, including the six county lines, and the agency’s internal grid and zone organizational system. One grid “does not exist,” a card notes, because of the structure of local highways.

Another card named the 11 CBP “towers” in the area. (Some of the tower names correspond to the gates and codes that WIRED is withholding due to their potential confidentiality.) The card notes the abbreviated names of two towers and the shared area of responsibility of a third tower.

The last card detailed an apparent internal system, “E3 BEST,” that allows officers to “record, investigate and adjudicate secondary referrals at USBP checkpoints” by allowing them to “query subjects and vehicles simultaneously through multiple law enforcement databases and create e3 Events for referrals resulting in an arrest.”

This potential exposure of confidential information comes amid a rapid hiring surge at CBP, with up to $60,000 in recruitment and retention incentives available to some new agents. ICE is also seeking to rapidly recruit, with its plan offering a $50,000 signing bonus and up to $60,000 in student loan repayment.

This story originally appeared at WIRED.com.