config:

Config file section

Valid in machine config files	YES
Valid in mode config files	YES

The config: section of your configuration files allows you to specify additional configuration files that will be read in after the current file is loaded. Here’s an example:

config:
    - machine.yaml
    - devices.yaml
    - game.yaml
    - textstrings.yaml
    - keymap.yaml

Note that each file is on its own line, which starts with a minus, then a space, then the file. (The space is important.) Also note that you can (optionally) specify a path, like this:

- config\machine.yaml
- config/my_game/machine.yaml

MPF will attempt to convert relative and absolute paths based on your OS, and it can deal with slashes in either direction.

MPF will then open those files one-by-one and merge their settings into the master configuration dictionary. The settings are merged together in the order the files are listed, so if multiple files specify the same configuration option then whichever one comes later in the list will overwrite any options that have already been specified.

You can also have config: sections in other config files, meaning that one config file can call another which will call another, etc.

Whenever MPF encounters a new config file, it will add it to the end of the list. And since files are processed in order, if there are any conflicting settings then the last file on the list will “win.” Also note that the framework will attempt to load the file from the current working directory (containing the config file that config: entry is from. If that fails then it will try the last known good directory that worked for a config file.