Access private, third-party repo in build environment

[fool]

It’s not a super-duper-edge-case; we aim to support it if not trivially

Assuming you have already tried these steps around using the SSH key:

[Support Guide] Using an SSH key via environment variable during build

Last checked by Netlify Support Team: December 2022 Some workflows require use of an SSH private key during build - for instance, logging in to a server to restart your backend, or using git clone on a private repo during build. There are better ways to accomplish this goal for most use cases, but in case you choose to do that, below is an approach that can work. First, create an ssh key and add the public key (shorter one) to your service (e.g. on your GitHub repo settings, or in ~/.ssh/auth…

and not been successful, then the submodule will likely be the best option, yes. If you want this let me know and I can configure and DM you a deploy key to use for that submodule.