code: func (j *Job) RequiredTargetMetadata() map[string]pkg.Set {
  	metadata := make(map[string]pkg.Set)
  
  	for _, key := range []string{
  		deprecatedXConditionPrefix + fleetMachineMetadata,
  		fleetMachineMetadata,
  	} {
  		for _, valuePair := range j.requirements()[key] {
  			s := strings.Split(valuePair, "=")
  
  			if len(s) != 2 {
  				continue
  			}
  
  			if len(s[0]) == 0 || len(s[1]) == 0 {
  				continue
  			}
  
  			if _, ok := metadata[s[0]]; !ok {
  				metadata[s[0]] = pkg.NewUnsafeSet()
  			}
  			metadata[s[0]].Add(s[1])
  		}
  	}
  
  	return metadata
  }
docs: // RequiredTargetMetadata return all machine-related metadata from a Job's
  // requirements. Valid metadata fields are strings of the form `key=value`,
  // where both key and value are not the empty string.