I emailed them last night and waiting for a reply.
Dirtrag
"The bike’s rear gets 148 x 12 mm Boost spacing and, while the seatpost size is only 27.2, the frame is internal dropper post compatible."
Singletracks
"Niner also touts internal dropper post routing on the frame, although with a 27.2 post size, your options will be limited."
Even Jensen advertise this as Internal dropper post compatible. It is mentioned with Di2... so maybe you do need to make a hole at the Di2 spot?
View attachment 90738
Anyways... will see what Niner has to say.
electronic actuated dropper?
and you don't need one. although i could use a $200 carbon post for my build - that $35 one scares me a bit.