Name: StravaAge: Founded by former Harvard rowers Michael Horvath and Mark Gainey in 2009.And it is what, exactly? A fitness app.How does it work? It uses GPS data to track your activities and is popular among cyclists and runners, who record their activity and then share it with a community. Also useful to the Jackal …As in ‘The Day of … ’? How so? An investigation by French newspaper Le Monde has used it to track the movements of Joe Biden, Donald Trump, Kamala Harris and other world leaders.T...