[seL4] Pull request of S91lighttpd

Hi, I'm trying to make a pull request as I want to make a very simple (yet useful) change to S91lighttpd file. I wonder where I can find this file in Git as I can find it locally in my build directory: build/overlay/etc/init.d/S91lighttpd but can not find it anywhere else in Git. I assume it is part of some prebuilt file system (overlay?) but still I can't find where this file system is in Git. Any help will be appreciated. Hugo