Newbie question about 'export' semantics

[Mark Petrovic]

Hi.  I am new to bird, and am studying an existing bird 1.6 configuration
to understand how the system it supports works.  Nothing is broken on my
system; I just want to understand how it works.

In the main bird.cfg within a bgp template, I see this

export filter calico_pools;

that calico_pools filter calls this via a bird function

     if ( net = 10.6.130.64/26 ) then { accept; }

Now, I correctly see this route as advertised when viewed from a BGP peer.
What I don't understand are the semantics of this if-statement.  In an
export statement, the docs say the relationship is from routing  table to
protocol

export:  "This is similar to the import keyword, except that it works in
the direction from the routing table to the protocol."

What confuses me is that there is *no* net = 10.6.130.64/26 in the local
routing table, so where is the value of "net" coming from such that the
if-net comparison can be made and the export makes sense works?  I know the
statement somehow does the right thing; I just don't know how to read and
explain it to others in the export context.

Can someone please help me understand how to read this?

Thanks.
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