The FOLIO system is not installed on the devices of any end users, but rather runs on a server, either hosted by a library or consortium; or by a commercial hosting provider, which can take care of the technical aspects of running a library system for institutions that prefer to outsource this task.
If a library or consortium host their own version of FOLIO on their own servers or a cloud server, they would need technical staff to maintain the platform, and to provide support for the end users of the system (although many support needs would hopefully be accomodated by the end users’ usage of the Help app in FOLIO).
If a library or consortium uses a software as a service (SaaS) solution from a hosting provider, the hosting provider would provide technical and potentially end user support. It seems likely that such hosting providers would want to provide a “filtered” version of the global FOLIO Store, which would e.g. show a “seal of approval” on apps that are known to run well on the hosting provider’s setup; or perhaps even only show apps that will be sure to work without problems, on the SaaS platform.
Depending on how the data is hosted, and on the privacy settings of each institution, and of each app, the data might be handled in various ways.