LibreOffice Online is a server service built from the main LibreOffice project code which provides display and collaborative visual editing of a range of document types. It does not include any form of file system. To be fully functional, it has to be integrated with file access and authentication provision from an underlying stack of software. For anything more than casual use it also needs to be deployed with due consideration for load balancing and other scaling issues. As such, LibreOffice Online can be considered an enabling technology for the public cloud of ISPs or the private cloud of enterprises and large organizations, when integrated - for example - with an enterprise file sharing or a groupware solution. see also the ebuilds here https://github.com/xdch47/gpo-xdch47 https://github.com/timeraider4u/libreoffice-online
libreoffice and/or nextcloud maintainers could be interested
Note LibreOffice Online includes "loolforkit" which allows privilege escalation to root: https://marc.info/?l=oss-security&m=161098249116896&w=4 Upstream's fix/approach to this has been incomplete so far. Since Gentoo does not currently ship libreoffice-online, there is nothing that needs doing now. But if LOOL is considered, this should be taken into account.