I work on a system in our lab that I connect to via SSH. Fetching a file via the web and pushing it to this machine is quite slow, and I want to pull on this machine directly. The trick to make this work is to use a TOKEN from gitlab and oauth2 as the username portion of the URL. For example

curl -O   https://oauth2:$CI_JOB_TOKEN@gitlab.com/api/v4/projects/$PROJECT_ID/packages/generic/$PROJECT_NAME/$PROJECT_VERSION/$FILE

The CI_JOB_TOKEN must be set to a token that has appropriate permissions on your project. Most of the values I wrote as envvars could be copy-pasted from the gitlab packages link on the web.