Introduced in version 2.1 (Released November 3rd)
Modules downloaded from the App store should not be changed. These are standardized modules and a developer should be able to expect the module to function as it does in other projects. Also the developer should be able to upgrade the App store module to the latest version without issues.
Should changes be made it is advised to create a new module for this.
This rule depends on the proper linking of modules to the App store module. Sometimes different modules have the same module-name and the project module might be linked to the wrong App store module. This can be fixed in the modules section of ACR.
Sometimes the module is linked to the wrong version of a module, for example ACR preserves the linked App store module version in a new revision, so when in the project the module is upgraded the link to the App store module in ACR also needs to be changed.