I would be very weary of this product. I used it a while ago on a project for a course I was taking. During my research, I found a FAQ where the creator stated that if ever asked to place a back door in it, he would.
I don't think any creator of any "secure" messaging product would claim something like this.
But, given the possibility of something like this happening either way, this is why clean open protocols are more important for decentralized software, than reference clients.
I browsed the tubes for a bit and couldn't find anything but the following, which is a Feature Request comment under Backend[1] mentioning a "controlled backdoor", possibly added by this contrib[2]. It reads as follows:
at the cost of getting scorned, but dead serious: a controlled backdoor, with an automatic audit trail, to be used by lawful agencies for keeping us safe. Bitcoin by design supports criminal activities, which undermine the community. A community messaging system should have a way of cleaning itself.
No one has ever asked if I would backdoor it. I certainly wouldn't; that would defeat the purpose. Someone below linked to a random user requesting this feature:
But, given the possibility of something like this happening either way, this is why clean open protocols are more important for decentralized software, than reference clients.