The projectDir/layers/local/conf/layers.conf file is mentionned a few times in the documentation. This file does not exist. We probably mean projectDir/layers/local/conf/layer.conf (without the 's').
$ ls layers/local/conf/layers.conf ls: cannot access layers/local/conf/layers.conf: No such file or directory $ ls layers/local/conf/layer.conf layers/local/conf/layer.conf