en-US/about_bolt_inventory.help.txt

inventory
  The inventory describes the targets that you run Bolt commands on, along
  with any data and configuration for the targets. Targets in an inventory can
  belong to one or more groups, allowing you to share data and configuration
  across multiple targets and to specify multiple targets for your Bolt
  commands without the need to list each target individually.
   
  In most cases, Bolt loads the inventory from an inventory file in your Bolt
  project. The inventory file is a YAML file named 'inventory.yaml'. Because
  Bolt loads the inventory file from a Bolt project, you must have an existing
  project configuration file named 'bolt-project.yaml' alongside the inventory
  file.
   
  When Bolt loads inventory, it loads the entire inventory, not just the
  groups and targets specified on the command line. If you've defined a
  target in multiple groups, this might result in target configuration that
  is different than expected.
 
Documentation
  https://pup.pt/bolt-inventory
  https://pup.pt/bolt-inventory-reference