That's an expected part of the entry. When you create a static route, it can to be put in a routing table, unicast or multicast (or both).
If you look at your current static routes at the CLI or GUI, you should see this defined. Unicast is the default so you don't actually have to select anything when you create a static route.
So the filter list needs to know which route table to reference to find the matching prefix. Check your current export rules in the CLI and you should see the entry for the route table on each of them. It will look something like this:
set network virtual-router default protocol bgp policy export rules <rulename> match route-table unicast