Once you enable the synchronization of the project's structure with Salesforce, the SyncData file is created in a static resource folder on your org (if it was not present before). In such a case, The Welkin Suite will notify you that SyncData will be created, and request your approval.
The SyncData file is a serialized file in a zip archive; it stores all service information about the project's structure for the current organization. After you've enabled the synchronization, whenever you make any changes in TWS, the SyncData file is updated to record these changes.
In case your org already contains the SyncData file, you will get a notification offering you to update the project structure according to this data.
If you select to disable the synchronization, you will be warned that, although the project's structure is no longer synced, the SyncData file is still present on Salesforce, where you can delete it manually.
In this section:
This also may be useful: