I bet that's not fiber, but just TM black color copper cable. Most house developer/contractor using low grade CAT3 cable which will degrade the connection quality.

Did you mean concealed? Concealed will be charge with non standard price (depends on contractor), if FREE installation, its surface only.
But for this case, TM contractor should seal the 5 cent size hole with white cement, else cicak, semut, ulat, lalat, ular, etc all come in from that hole.

@mistyblu , dont forget to rate your TM contractor via SMS. Usually TM HQ will called to followup if received low rating.