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NextCloud supports "federated sharing", which permits users to share files between different NextCloud services, and browse user directories on other services. Users are given a globally unique scoped identifier that resembles EduPersonPrincipalName. If EPPN is used as the NextCloud username then a user's identifier is scoped twice.
The External Storage plugin allows remote data storage to be used, including other NextCloud or OwnCloud services.
Caveats
Speed
The display of Collabora is generated by sending many tile-like images over the web as individual files, and is rather slow. Over a normal broadband internet connection the display is not quite fast enough to keep up with typing.
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