Many thanks @JammyDodger. We were thinking of being a bit more automated. We planned to export our current list of emails, then extract those that matched the hipo list of university domains, and then import that new list into discourse under the auto approve email domains key. Using python and pandas for the numercal processing. I guess that route is not supported? Or do we, or can we, have programmatic access? (PS: with reference to your screenshot, gmail.com is that last domain name we would dream of automatically approving.)
Oh, and can we use wildcards like: *.tu‑berlin.de to account for departmental information being included, say maths.tu‑berlin.de.