When using some Linux installation of VSCode or Codium, it's bind to https://open-vsx.org instead of the marketplace.

Open-VSX teams provides publication instructions on https://github.com/eclipse/openvsx/wiki/Publishing-Extensions.

If this require to much work, it's possible to fill a pull request in this repository: https://github.com/open-vsx/publish-extensions/