I successfully installed 32-bit Tumbleweed to a logical drive in an extended
logical partition, /dev/sda6, on my laptop, and the installer set the FS type
to btrfs. After I replaced the CPU with a 64-bit chip, I decided to replace
Tumbleweed with LEAP 15.1. I selected expert, existing partitions and import
mount points. I ran into multiple problems, described in
https://forums.opensuse.org/showthread.php/536788-Unable-to-replace-bootloader-from-Tumbleweed?highlight=shmuelmetz,
and wound up changing the FS type to ext4, which worked; the generic bootloader
in the MBR can handle an active logical drive.

The failing scenarios are trying to install the bootloader into MBR when there
is little space before the first partition, and trying to install the
bootloader into the PBR of a logical drive (the installer puts it in the PBR of
the extended partition instead of the PBR of the logical drive.