hrm. Either #babeld on #openwrt is buggy, or I don't understand how the filters are supposed to work...

With a general

redistribute local allow

rule, the IP address I want is distributed, along with other stuff.

With

redistribute local ip fdxx:xxxx::n/128 if <interface> allow
redistribute local deny

The IP address is not distributed - even though It's the exact same IP address.

WTF!?!?!