Well, first of all, K9 regularly beta tests their new versions before release already.

Being launched under the Thunderbird brand, though, is expected to hit a much wider audience than just K9 users. And being a first impression, they want to do everything they can to make that impression a solid one.

The main thing they want testing for is the migration tool from a k-9 app installed and configured already on the device, which would be net new code.

Because they took an existing, completely spyware free app- K9 and added invasive telemetry to it.

Now they need you to test it so they can track you and get your data.