Missing IPv6 default route on protocol kernel and table master6

[Bernd Naumann]

Hey *,

I do not see a default route for IPv6 on the `kernel` protocol (or 
`table master6`), like with IPv4, therefor I'm unable to export it via 
`ospf`.

I'm running bird 2.0.8 on OpenWRT 21.02, Kernel 5.4.154.

At first I thought it's because I had `pppoe-wan` not covered in `proto 
device` and `direct`, but `proto kernel` uses `learn yes` and with IPv4 
it makes `bird` aware of the default route, but not so with IPv6. (At 
least I assume so. Please correct me on possible misconceptions.)


```
root at cpe:~# birdc show route for 0.0.0.0
BIRD 2.0.8 ready.
Table master4:
0.0.0.0/0            unicast [kernel_ipv4 08:16:19.473] * (10)
         via 62.155.247.X on pppoe-wan

root at cpe:~# birdc show route for ::/0
BIRD 2.0.8 ready.
Network not found

root at cpe:~# ip -6 route show default
default from 2003:e4:bf24:XX00::/56 via fe80::f6cc:55ff:fe42:1a94 dev 
pppoe-wan proto static metric 512 pref medium
default from 2003:e4:bfff:XXXX::/64 via fe80::f6cc:55ff:fe42:1a94 dev 
pppoe-wan proto static metric 512 pref medium
default from fde6:a09a:b373:f0::/64 dev pppoe-wan metric 1024 pref medium
default from fde6:a09a:b373:ff::/64 dev pppoe-wan metric 1024 pref medium

```

I have now:
* `pppoe-wan` covered in `device` and `direct`
* `kernel` with
   - `learn yes`, and
   - `import all`, and
   - `export filter { accept; };`
* `ospf` even has `interface "pppoe-wan" { stub yes; };` and `export all`.

But still ::/0 is not present in `bird`. Am I missing something 
(obvious) here?

Thanks for advice and help.
Bernd


PS: Can I show/filter routes on `protocol kernel` which are "learned" 
and not "imported"?