> If you check the tags, you can find the source.

I tried using https://overpass-turbo.eu/s/1uZ9

    <tag k="name:fr" v="Corridor Méditerranéen"/>
    <tag k="network" v="RNE"/>
    <tag k="ref" v="RCF 6"/>
    <tag k="route" v="railway"/>
    <tag k="type" v="route_master"/>
    <tag k="wikidata" v="Q2895444"/>
    <tag k="wikipedia" v="fr:Corridor méditerranéen"/>


so, was it copied from wikipedia page? Or https://fr.wikipedia.org/wiki/Corridor_m%C3%A9diterran%C3%A9en more specifically? But it does not appear to have such info