Question regarding Bounce Management

Good day,
i got a question regarding bounce management. I have 85K bounce messages collected. Now i want to process them, but first i would like to test.
Is there somehow a test mode, which is NOT deleting emails from the mailbox but just checking and reporting, what got identified as spam?
Maybe i have to setup more rules so i have to check many times, before i activate the deletion of bounces.
What happens to the mails which dont fit to a bounce rule? Does they stay in the mailbox so i can make new rules afterwards and process them then?

It would be great, if someone can guide me through my question because i have concerns that all mails in the mailbox gets deleted and i will later send newsletter to unexisting or problematic emails.

Thank you so much
BoneCracker

phplist downloads and deletes the bounces from the mailbox and adds them to the database. A bounce will remain in the database until it is deleted as a result of a bounce rule or another result of an action by an admin.

Bounce rules will be applied to all bounces, even those that have already been matched, so it makes sense to delete a bounce when it is no longer needed.

Thank you very much Duncan.
I did not know about this type of handling. It seems to be okay to download now the bounces and process them.

Thank you very much

Daniel