16 files declare their use of VariablesSet in Business Rules 2.x

BusinessRulesConditionPluginInterface.php in src/Plugin/BusinessRulesConditionPluginInterface.php

BusinessRulesItemPluginBase.php in src/Plugin/BusinessRulesItemPluginBase.php

BusinessRulesItemPluginInterface.php in src/Plugin/BusinessRulesItemPluginInterface.php

BusinessRulesProcessor.php in src/Util/BusinessRulesProcessor.php

DataComparison.php in src/Plugin/BusinessRulesCondition/DataComparison.php

EntityEmptyVariable.php in src/Plugin/BusinessRulesVariable/EntityEmptyVariable.php

EntityFieldVariable.php in src/Plugin/BusinessRulesVariable/EntityFieldVariable.php

FetchEntityVariableAction.php in src/Plugin/BusinessRulesAction/FetchEntityVariableAction.php

FillEntityVariableFields.php in src/Plugin/BusinessRulesAction/FillEntityVariableFields.php

LoopThroughFieldVariable.php in src/Plugin/BusinessRulesAction/LoopThroughFieldVariable.php

LoopThroughViewResult.php in src/Plugin/BusinessRulesAction/LoopThroughViewResult.php

ScheduleController.php in src/Controller/ScheduleController.php

SetFieldValue.php in src/Plugin/BusinessRulesAction/SetFieldValue.php

UrlVariable.php in src/Plugin/BusinessRulesVariable/UrlVariable.php

UserVariable.php in src/Plugin/BusinessRulesVariable/UserVariable.php

UserVariableHasRole.php in src/Plugin/BusinessRulesCondition/UserVariableHasRole.php