During installation of Leap 42.2, if Import Mount Points is chosen and the
imported mount points include a Btrfs file system, then the Enable Snapshots
checkbox is deselected and no snapshot configuration is made if the
installation is completed.  This has been reported for Tumbleweed as bug
966637.

This can be verified without requiring an actual installation.  This does
require a PC with an existing Btrfs filesystem.  Mine has a straight-forward
Btrfs root filesystem.

Steps to verify:

1.Launch the installer
    (I (U)EFI-booted the installer)
2. At the partition set up step choose "Expert partitioner" 
3. Find an existing Btrfs file system in the proposal
    3.a If none exists, create one
4. Right-click the existing Btrfs file system, choose Edit, then press the
Subvolume Handling button
5. Note that the Enable Snapshots checkbox is checked
6. Exit out of this dialog
7. Now click on "Import mount points", find the mount point file (fstab) with
the existing Btrfs partition, and accept
8. Right-click this Btrfs file system, choose Edit, then press the Subvolume
Handling button
9. Note that the Enable Snapshots checkbox is not checked
     9.1 If you absolutely want to verify this bug, complete the installation
from here
10. Exit this dialog and Abort your way out of the installation to preserve the
existing installation

If this behavior is by design, then the release notes, at least, should be
updated to warn people of it.