Namespace overlap

Given an existing default namespace:

namespace inbox { type = private separator = / prefix = location = sdbox:/var/mail/%d/%n/sdbox inbox = yes hidden = no list = yes subscriptions = yes }

And mailboxes like: INBOX INBOX/Archives INBOX/Archives/2018

if I then define a new namespace:

namespace archives { type = private separator = / prefix = Archives/ location = mdbox:/var/mail/%d/%n/Archives/mdbox subscriptions = no list = children }

What will happen to the previous existing mailboxes & mails? Will they simply be "masked" by the new namespace and remain pending other operations? Or would they be moved/deleted?

If they remain - is it possible to refer to the old mailboxes via either IMAP or doveadm?

-- Daniel