http://maps.me/en/help says

Can I record tracks in GPX format in MAPS.ME?

So far, you can use "Recent track" option (app's settings – Map – Recent track). It allows you to record travelled path for a ceratin period and see it on the map. You can also convert GPX to KML or KMZ and import tracks and bookmarks in KML or KMZ format.

But this doesn't describe where the GPX track actually is, so it doesn't really answer the question. Where can I find it?

On the phone's memory I can find gps_track.dat but that doesn't seem to be GPX or KML.