ASM and IPv6 Compatibility
ASM isn't just a file system.  It's also a volume manager.

An ASM instance is a cut-down Oracle instance that database instances talk to in order to find out how to access the blocks they need.  The ASM instance doesn't write data to or read data from the disks itself, it only provides the information that the database requires in order to do this.

This communication is over the network, so involves IP.  Hence the note about IPv4/IPv6.