Public flight tracking sites like Flight Radar 24 collect ADS-B data from aircraft all around the world. (There are also sites tracking AIS data from ships, and sites that archive aviation weather reports called METARs for most major airports.) There are apps that let you identify a flight by pointing your smartphone at it. The flight tracking sites also have an archive, but the free version usually only goes back a few days, and you need a paid subscription to access it. That's where this comes in handy:
In case you didn't know ADSB Exchange now offers 1 year of flight data playback. It displays some military flights that FlightRadar24 does not. You can access the replay function at https://globe.adsbexchange.com/?r .
Anyway... I've checked for the time of this sighting, and there's nothing showing on ADBSExchange that isn't on FR24.
Also they offer the download of kmls (click on the plane, button "Export KML" appears bottom left.)