The yellow arrow shows a frame out of the chassis. This is being made to hold the body from where the 15" extension is done. It will not only strengthen the body but will also be like a support to the front seats.
Also if you see in the first picture, the newly installed "DHOLKI" of the cylincer is a bit low, so it will be moved in the place which is being encircled in the 2nd pic.

