No idea why this was removed after the Kopano fork, but this is definitely something you guys should look into again.
Even in mid-size environments I was using this for all my customers, as it was possible to quickly restore or even move single inboxes. Please also consider bringing back the PST Import tool. And no, Outlook isn't always an option, especially in mixed environments where many workstations could also be Linux based.
Thank you for your time and consideration. Keep up the great work! 🙂