International airports are a border and fall under CBP. So do "vessels", busses that may move between countries, etc.

> Employees traveling internationally on behalf of an organization must take steps to protect sensitive, confidential, or proprietary data carried on electronic devices. U.S. Customs and Border Protection (CBP) has broad authority to inspect electronic devices—regardless of citizenship—at U.S. airports, land borders, seaports, and preclearance facilities abroad.

https://www.potomaclaw.com/news-Border-Search-Inspection-of-...

It's extremely complicated:

https://cdt.org/insights/no-warrants-and-half-a-dozen-differ...