MyRepublic are renting pre built fiber infrastructures in places where fiber infrastructures are open for 3rd party ISP to lease. For example in Singapore, they use NetLink Trust (formally Opennet), in NZ they use UFB (Chorus), in Australia, NBN (NBN Co). The only country they build their own fiber is in Indonesia, because their Indonesia partner Sinarmas is a large conglomerate there and they own some of the fibers, so MR juz use it and roll it out for FTTP. They will most likely use TM's HSBB as HSBB covers a large footprint now.

Cheer,
Jack.