The deprecations triggered by your project are listed by going on the "Issues" main navigation item and then clicking on "Deprecations".
The UI is similar to the Exception/Error tracking with a few changes:
Enabling logging of Deprecations with Tideways requires to be enabled through PHP configuration.
There is currently no workflow operations for deprecations at the moment.
Deprecations are aggregated based on their message alone, not based on the stacktrace as errors/exeptions are. This means two deprecations with the same message are aggregated with the stacktrace showing the last occurrence of both.
Deprecations do not count into the Failure Rate of a project and you will not get notified about them as part of the Error/Exception Notifications.