I did some digging (when I should have been working on my fiat job). Here are my findings:
TLDR: it shouldn't work for nodes with only private channels since ligess is not passing the parameter `private` to `lnd`'s `AddInvoice` RPC method:
Here are the relevant code parts:
1 - `ligess` calls una's `createInvoice`
https://github.com/Dolu89/ligess/blob/d8c71626a403a5d40f6f88b134506d7776a34d3a/router.js#L47-L53
2 - una translates and passes these parameters:
3 - una calls the `lnd`'s `AddInvoice` using REST
4 - That method has these docs (check the field `private`)
https://lightning.engineering/api-docs/api/lnd/lightning/add-invoice
5 - On `lnd`'s code base, that field has no explicit default and since it's in rust, the defaults to false
In order to fix this, one would need to patch botch ligess and una to pass the `private=true` parameter.
It seems most LN address server didn't explicitly set private route hints or have configuration for that.
I found that https://github.com/bumi/lnme has config for that. I already use it for my private LN address outside of nostr. But, i haven't decent skill in Go to patch it to make NIP-57 compatible 😅
