RaceTale Runner Tools is the open-source maths behind the free runner tools at blog.racetale.com: pace and finish time, Riegel race predictions, split plans, heart rate zones, spectator passing times and GPX start/finish trimming. It ships as the racetale-pace npm package and a browser extension (Chrome, Edge, Firefox). MIT licence. Source: https://github.com/krasenslavov/racetale-runner-tools