When a Visual Studio Tools for Office solution is published, the solution files are created in the publish folder in the following structure:
ClickOnce creates a new deployment manifest for each version of your Office solution. For example, for the first version of a solution called OutlookAddin1, the publish process creates a version-specific deployment manifest in the version-specific subfolder called OutlookAddIn1_1_0_0_0. This subfolder is in the Application Files folder. In addition, ClickOnce puts a copy of the deployment manifest in the top-level publish folder.
The next incremental publish creates a version-specific deployment manifest in the version-specific subfolder called OutlookAddIn1_1_0_0_1. It also replaces the deployment manifest in the publish folder with a copy of the most recent version-specific deployment manifest.
ClickOnce appends the .deploy extension to assemblies. This way, a secured installation of Internet Information Services (IIS) will not block the files because of an unsafe extension. After the files are downloaded, ClickOnce removes the .deploy extension before installing the solution into the ClickOnce cache. For more information, see <deployment> Element.