We are working on the payments documentation in MDN. It probably makes sense to pull that documentation over to devhub from MDN with the other developer documentation.
For reference, these are the main docs right now: https://developer.mozilla.org/en-US/docs/Apps/Marketplace_Payments/FAQ https://developer.mozilla.org/en-US/docs/Apps/In-app_payments https://developer.mozilla.org/en-US/docs/Apps/Marketplace_Payments If you look at the in-app payments doc you'll notice that this is focused on developers at the audience. So, yeah, I think it would make a lot of sense to live on the devhub, especially since it requires interaction with devhub pages. Fred, sadly I did not get a chance to chat with you about this while in MV. I talked with tofumatt about it a little though.
Here is another payment-related doc I found and exposed again: https://developer.mozilla.org/en-US/docs/Apps/Validating_a_receipt
I believe this is now closed (at least for this iteration) https://marketplace.firefox.com/developers/docs/payments Fred?
Yeah Mark has added the good stuff to the docs. Thanks! I'm closing this but if andym disagrees, please reopen :)