The Register attended
a talk about Ubuntu’s upcoming Core Desktop immutable distribution.

We suspect that Core Desktop might yet be the tool that validates
Canonical’s Snap format and helps to overcome some of the
resistance it faces. Snap’s single-file distribution format is
simple and enables transactional installation – including,
critically, rollback – without a fancy filesystem underneath, or
elaborate distribution methods such as libostree.

Source: LWN.net – Canonical reveals more details about Ubuntu Core Desktop (Register)