that was my mistake i meant /etc/portage/repos.conf file or directory. I want to add my own overlay to it so that it gets included in the build image when the cbuildbot looks at what repositories it is supposed to build. According to the chromium documentation, I have to create my board overlays, then I add my overlay to their build process, etc. But according to the gentoo documentation I need to add something like this to the repos.conf file. because that's their preferred method of adding overlays to the build process.
/etc/portage/repos.conf/brother-overlay.conf
Adding the brother overlay
so could you tell me where the chromeos repos.conf file is, thanks