Maintenance Process Definitions
Maintenance process definitions are special process definitions that are supposed to run in the background and not be visible in the default All (Non-Maintenance) Processes monitor filter. They will show up in the Custom Maintenance (Background) Chains filter, though. This allows you to craft specific background processes to perform regular household tasks in the background without invading your production processes in the default filter.
See Also
JobChain JobDefinition ProcessDefinition