Simple definition
Filesystem in Userspace (FUSE) lets applications implement filesystems without writing kernel filesystem modules.
Purpose and use
FUSE, Filesystem in Userspace, allows a userspace process to provide a filesystem.
How does it work?
The kernel forwards operations to the userspace component, which supplies data and metadata according to its implementation.
Example and verification
A remote-file mount can therefore expose a conventional directory tree to local applications.
Points to watch
Availability, permissions and performance also depend on the userspace process and underlying service.
In short
FUSE is an implementation framework, not a complete definition of storage behavior or guarantees.