prow/config/config.go
func (ownersDirBlacklist OwnersDirBlacklist) DirBlacklist(org, repo string) (blacklist []string) {
	blacklist = append(blacklist, ownersDirBlacklist.Default...)
	if bl, ok := ownersDirBlacklist.Repos[org]; ok {
		blacklist = append(blacklist, bl...)
	}
	if bl, ok := ownersDirBlacklist.Repos[org+"/"+repo]; ok {
		blacklist = append(blacklist, bl...)
	}
	return
}
func (ownersDirBlacklist OwnersDirBlacklist) DirBlacklist(org, repo string) (blacklist []string) {
	blacklist = append(blacklist, ownersDirBlacklist.Default...)
	if bl, ok := ownersDirBlacklist.Repos[org]; ok {
		blacklist = append(blacklist, bl...)
	}
	if bl, ok := ownersDirBlacklist.Repos[org+"/"+repo]; ok {
		blacklist = append(blacklist, bl...)
	}
	return
}
// DirBlacklist returns regular expressions matching directories to ignore when
// searching for OWNERS{,_ALIAS} files in a repo.