Follow https://stackoverflow.com/questions/73351227/how-to-recover-deleted-repository-in-azure-devops to restore it.
The event should be recorded in the audit logs ( https://learn.microsoft.com/en-us/azure/devops/organizations/audit/auditing-events?view=azure-devops ) assuming you have these enabled (https://learn.microsoft.com/en-us/azure/devops/organizations/audit/azure-devops-auditing?view=azure-devops&tabs=preview-page#enable-and-disable-auditing ). Auditing is turned off by default for all Azure DevOps Services organizations
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hth
Marcin