I've been wanting to have a watch only wallet on Bitcoin core, so that I could check transactions of my cold storage devices from my node on the command line. Alas, core doesn't support BIT-39, so I couldn't create a core wallet and import my cold storage xpub into it.

I decided to go for a gui wallet which I could connect to my full node that could import my xpub for the moment, and so I've downloaded Sparrow wallet (I never tried it before), and have successfully imported the xpub for a cold wallet. I'm starting to like Sparrow wallet a lot, by the way. :-)

Sparrow wallet scans your the blockchain and stores its wallets inside the bitcoin core directory, on a sub-directory called cormorant (no idea why that name, yet...), and interestingly, core recognizes those wallets and is able to use them.

And that is how I accidentally have found a way to build my wanted watch only wallet on core.