So I had a discussion with the developer Cesar earlier today about this, and yes it uses outbound relays.
However, I've also noticed sometimes it "overwrites" my published list of relays and pre-populates with 25 of what I think are default ones... so yeah, not quite sure what's going on. Maybe it is using an indexer which was out of date.
Tagging nostr:npub1cesrkrcuelkxyhvupzm48e8hwn4005w0ya5jyvf9kh75mfegqx0q4kt37c here in case this might provide a hint for him.