It operates in userspace, and will work on top of any Linux file system.
Files provided by commits are by default immutable, done by mounting the filesystem itself as read-only.
OSTree allows for two mutable directories for storing user data: /etc and /var.
It provides a mechanism to allow filesystem trees to add configuration files to /etc while also allowing system administrators to edit those files in a persistent manner.
libostree is used by various Linux operating systems and tools: This article incorporates text available under the CC BY 3.0 license.