When Gearset first connects to a Salesforce org, it requests a range of permissions:
The primary permission that underlies this is the Modify all data permission. To use Gearset to deploy both metadata and data between your orgs, the user (actually, the user's profile) you used to authenticate against the org must have this permission.
Why does Gearset need this permission?
As a deployment tool, Gearset needs the ability to read and write org metadata and data.
What if I'm not using data deployment?
There is an Administrative Permission named Modify Metadata Through Metadata API Functions.
In theory, this setting should be enough to allow you to use the metadata functionality of Gearset. However, we've found some inconsistencies with this setting. Even if you're only looking to utilize metadata, it's still sometimes necessary to grant the Modify All Data permission.
Our recommendation would be to grant the Modify All Data permission. But please be aware that unless you're using Gearset's data loader, the app will never read or write any org data.
Can I control this access?
Gearset's access to an org can be revoked from within the org at any point by the end user, via the Connected Apps OAuth Usage page.
What permissions are needed to use Backup and restore?
We have a separate documentation that outlines all the necessary permissions required to authenticate a Salesforce user to use our Backup solution along with the data and metadata restore functionality.
Check this article for more information:
Gearset backup & restore - User permissions