If Repoman acts as a custom composer installer, the developer would require the necessary packages (like normal), including any MODX packages (identified by the "type"), and they would need to list repoman as a dependency so that the custom installer would know how to install the packages where type="modx-package"
See instructions here: https://getcomposer.org/doc/articles/custom-installers.md
If Repoman acts as a custom composer installer, the developer would require the necessary packages (like normal), including any MODX packages (identified by the "type"), and they would need to list repoman as a dependency so that the custom installer would know how to install the packages where type="modx-package"