I don't think it's prohibited, see linked issues below. I have been keeping an eye on the project and that feature for several years. I am using zfs snapshots locally and borg backup for now. It is not comparable but does the job for now.
XTX Markets | Junior and Senior System Engineer | Onsite - London, UK | Full time
XTX Markets is an award winning financial trading company which specialises in electronic market making. We trade in large volume on a significant number of the world’s trading venues and exchanges, entirely in an automated fashion, with our seventy staff members initiating many millions of trades each day.
The IT Infra group provide a technology platform for the firm. We are a team of nine people currently. The scope of our responsibilities are maintaining the network, server operating systems, storage, enterprise applications, end user computing environment and datacentre facilities. We exhibit special expertise in large installation system administration, performance optimisation, and compute cluster design.
XTX is a company that rewards people on merit and excellence, not necessarily on experience, avoids the bureaucracy of large organisations and maintains a flat hierarchy. Work is fast paced, in abundance, so we ensure decision making is efficient and changes are quickly implemented. People working at XTX enjoy a culture of trust, innovation and scientific rigour. It’s a collaborative and friendly environment where people are highly engaged with their work.
https://github.com/perkeep/perkeep/issues/792 https://github.com/perkeep/perkeep/issues/1076