Joomla extension installation rollback process

[Izhar Aazmi]

I tried to study the Joomla Installer codes but I could only understand it partially. Something like push step etc.

I'd like to know how the rollback mechanism works in Joomla in case of an installation failure and how to utilise the same for any extension. Is there any documentation anywhere regarding this? 

As an extension developer is there any extra coding to do or any additional specification to follow?

What when we are using custom install script, and what if it is just a simple installer with files, sql and manifest file only.