This is the local basilica, built during Early Christianity. I could not find much information, much of its building materials seem to stem from the nearby agora and the Kronos temple.
A book has since been published, information about it mentions: "Tlos was among the important episcopal centers established in the Lycian Region with the Christian Period. Tlos City Basilica, built in the second half of the 4th century AD, is one of the earliest basilicas in Anatolia. Built in the style of the cruciform basilicas of the period, the building measures 55 x 34 x 20 m. Covering the floor of the basilica like a carpet, 600 m2 mosaic flooring prepared in the opus tessellatum technique, murals, architectural elements, inscriptions, coins, seals, ceramics, glass and anthropological finds, important information about the historical process of the basilica, which was used until the 13th century with repairs in different periods.