We provide full data residency for our Cloud app. We do not store any in-scope data on our side. Everything is stored on the Atlassian site, and the worklogs, which are created using the Timesheet Builder app, are created as standard Jira worklogs.
Our app sends requests to Jira, and all data is processed on Atlassian side.
Read more about in-scope data: https://support.atlassian.com/security-and-access-policies/docs/understand-data-residency/#In-scope-product-data