Update:

Vendo Digital Downloads is live (https://vendo.bitejo.com). Buy and sell digital products for Monero (XMR), such as ebooks, music, gift cards, game keys, links or premium content. 100% KYC-free and non-custodial. Sellers receive payment directly to their Monero wallet with zero fees, and buyers can download the product immediately after 1 confirmation. A Monero-friendly alternative to Gumroad and SatoshiBox.

Source code: https://codeberg.org/anarkio/kuno