You may have heard of the “top 9%” Eligibility in Local Context at UCs in California.
What they actually do here is that high schools that want to participate submit the courses and grades of their top 12.5% students to UC. UC then recalculates the GPAs of those students. UC then records the top 9% threshold GPA for the high school from these GPAs, so that GPAs of applicants in the next cycle are compared to that threshold GPA to determine Eligibility in Local Context.
Note that this means that (a) the high school’s notion of GPA and class rank is irrelevant, and (b) the applicant is compared to a baseline set by a recent previous class, not other students in the current class (so cutthroat behavior is not rewarded).
In a less formalized fashion, a college which gets a lot of applications from a non-ranking high school can infer a relative ranking of these applicants from their GPAs (whether or not recalculated by the college).