platform/platform-resources/src/META-INF/ExternalSystemExtensions.xml

<idea-plugin>
  <extensions defaultExtensionNs="com.intellij">

    <postStartupActivity implementation="com.intellij.openapi.externalSystem.service.ExternalSystemStartupActivity"/>
    
    <!--Generic services-->
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.ExternalSystemFacadeManager"/>
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.RemoteExternalSystemCommunicationManager"/>
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.InProcessExternalSystemCommunicationManager"/>
    <applicationService
        serviceInterface="com.intellij.openapi.externalSystem.service.notification.ExternalSystemProgressNotificationManager"
        serviceImplementation="com.intellij.openapi.externalSystem.service.remote.ExternalSystemProgressNotificationManagerImpl"/>
    <applicationService serviceInterface="com.intellij.openapi.externalSystem.service.project.PlatformFacade"
                        serviceImplementation="com.intellij.openapi.externalSystem.service.project.PlatformFacadeImpl"/>
    <applicationService serviceInterface="com.intellij.openapi.externalSystem.service.project.ExternalLibraryPathTypeMapper"
                        serviceImplementation="com.intellij.openapi.externalSystem.service.project.ExternalLibraryPathTypeMapperImpl"/>
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.project.ProjectStructureHelper"/>
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.internal.ExternalSystemProcessingManager"/>
    <projectService serviceImplementation="com.intellij.openapi.externalSystem.service.notification.ExternalSystemNotificationManager"/>

    <!--Project structure management services-->
    <applicationService serviceImplementation="com.intellij.openapi.externalSystem.service.project.manage.ProjectDataManager"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.ProjectDataServiceImpl"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.LibraryDataService"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.ModuleDataService"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.ContentRootDataService"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.LibraryDependencyDataService"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.project.manage.ModuleDependencyDataService"/>
    
    <!--Tool window services-->
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.task.ToolWindowModuleService"/>
    <externalProjectDataService implementation="com.intellij.openapi.externalSystem.service.task.ToolWindowTaskService"/>
    
    <!--Execution-->
    <programRunner implementation="com.intellij.openapi.externalSystem.service.execution.ExternalSystemTaskRunner"/>
    <programRunner implementation="com.intellij.openapi.externalSystem.service.execution.ExternalSystemTaskDebugRunner"/>
    
  </extensions>

</idea-plugin>