Train-dev doesn't live here anymore per T323225. It lives at https://gitlab.wikimedia.org/repos/releng/train-dev. The master branch has been renamed to 'main'. You can change your remote to gitlab via the following commands:
git remote set-url origin https://gitlab.wikimedia.org/repos/releng/train-dev.git
git remote set-url origin git@gitlab.wikimedia.org:repos/releng/train-dev.git