In 2012 Transjakarta ordered Zhongtong Bendy buses, among bus fans they are known for having very cold Air-Conditioning, 3 batches came in 2012 and 2016 given to Bus operators DAMRI(red), PPD(blue) and Transjakarta(red) and powered by Doosan GL11K CNG engines
The first and second batch (second batch not shown)
Zhongtong LCK6180GC by Anindra Pratama, on Flickr
Zhongtong LCK6180GC by Anindra Pratama, on Flickr
Interior :
Zhongtong LCK6180GC interior by Anindra Pratama, on Flickr
Zhongtong LCK6180GC interior by Anindra Pratama, on Flickr

Third batch operated by PPD. These buses arrived at Jakarta in 2016 but due to contract controversies and a fine imposed on PPD over it's delayed arrival hold it's debut until October 2019!, unlike the previous batch, they feature different seating and arrangement (fleet number 0763 is an exception as it's similar to the previous series)
New Zhongtong Bendy Bus 1 by Anindra Pratama, on Flickr
New Zhongtong Bendy Bus 2 by Anindra Pratama, on Flickr
PPD Zhongtong LCK6180GC by Anindra Pratama, on Flickr

When the first time I saw the pictures of the buses, I thought they are low floor bus as I saw the interior they even don't have any step at the entrance and exit,
but when I look closer, well, it seems like they a platform higher than the sidewalk for the buses to stop like a train,
so that means all the air-condition unit and CNG fuel tanks are under the floor if I'm correct.

魔法先生 Super Bus on 2020年10月25日 00:08:43: When the first time I saw the pictures of the buses, I thought they are low floor bus as I saw the interior they even don't have any step at the entrance and exit,
but when I look closer, well, it seems like they a platform higher than the sidewalk for the buses to stop like a train,
so that means all the air-condition unit and CNG fuel tanks are under the floor if I'm correct.

You are right, the fuel tanks are located underneath, don't know about the AC