Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi Olivier, from the my tests and further research, the custom field data will not be included in the TSV file. Currently, each row in this file includes the data and time info for the event, customer name, customer email, customer phone number, customer address, staff assigned, service selected, location, and appointment duration. There is no other places to get the report from my limited knowledge.
I suggest submitting this feature request in Bookings feedback site: Microsoft Bookings UserVoice. Then the engineers there would be able to review your idea and incorporate it into product planning queue.
Regards,
SD