node.js – GitHub action with access to private repo

I would like to run the CI part of my Node / Ionic project where I just yesterday added a custom capacitor plugin – repo A.

This plugin sits in repo B.

On my dev machine I added B as

npm install --save

to project A.

package.json now contains

"B": "git+",

and I pushed this to my current merge request.
However, the CI pipeline is telling me now:

  npm install
  shell: /usr/bin/bash -e {0}
npm ERR! Error while executing:
npm ERR! /usr/bin/git ls-remote -h -t https://***
npm ERR! 
npm ERR! remote: Repository not found.
npm ERR! fatal: repository '' not found
npm ERR! 

Project B is a private repo. My account owns both repos and I am using my newly created Personal Access Token.

What should I check? I can pull the repo on my local, but there I am setup with my git+ssh env credentials too, so it might work just because of that…