It's just a one liner:
https://docs.flutter.io/flutter/widgets/LocalHistoryEntry-class.html

"An entry in the history of a LocalHistoryRoute."

Which links to a slightly larger description in LocalHistoryRoute.

Maybe this just needs to link to a navigation tutorial? @alardizabal expressed some confusion attempting to use the API.