Would help if the comment expanded on what a Shufflecake is. For anyone else reading this, apparently it's "plausible deniability for multiple hidden filesystems on Linux."
More: Shufflecake is made of two components: dm-sflc, which is a kernel module implementing the Shufflecake scheme as a device-mapper target for the Linux kernel, and shufflecake-userland, which is a command-line tool allowing the user to create and manage hidden volumes. The kernel module must be loaded before using the userland tool.
https://news.ycombinator.com/item?id=33586503
https://shufflecake.net/#news