Hi @karthigsn,
what did you expect exactly?
Currently, there is no variant to this module in the core.
Do you have create one and request support ?

Edit:
Seems linked to this request even if it's not the same username: rogerclarkmelbourne/Arduino_STM32#442

@fpistm

http://www.rakwireless.com/en/module/lora/RAK811

Can you help me in programming the RAK811 which has STM32L151. I could not find Generic STM32L151 in Board manager of Arduino.

Thanks
Karthi

It is a module not a board like this one using STM32L052T8Y6 :
http://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-eval-tools/stm32-mcu-eval-tools/stm32-3rd-party-evaluation-tools/i-nucleo-sx1272d.html
The RAK811 module comes with a preloaded AT-Command software and it can be controlled from an external host. You have to connect it to a board and send AT command to drive it.

The RAK811 If it can be programmed, you used the IDE SW432 to do it. has the chip L151

There is several doc for this module:
http://www.rakwireless.com/en/download/RAK811/Software%20Development
Also the FW upgrade tools:
http://www.rakwireless.com/en/download/RAK811/Firmware%20upgrade
Don't know if SWD pins are external.
There is a dev board to use with this module and also an Arduino library to use this module.
That's all I can do.