Bit of history, maybe off topic.
Remastersys was (and is) a superb script. Its creator had a web site and a forums too. But, after so many arguments, attacks, etc, he dropped the development and closed the forums. Antoni Norman created Pinguy OS, which was also doing so well, but money is needed to run the website, so one day he went off air saying he's thinking of killing the project. While he was still developing, he forked the Remastersys to support UEFI for both 32 and 64 bit.
http://pinguyos.com/2015/09/pinguy-b...upremix-buntu/
If you open /usr/bin/PinguyBuilder, you'd see how the script is constructed.
If you want to look at the original Remastersys, someone had uploaded it here,
https://launchpad.net/~mutse-young/+...rsys/+packages