It’s mentioned in the article. It’s more to do with business intelligence than security. A simple auto-incrementing ID will reveal how many total records you have in a table and/or their growth rate.
> If you expose the issues table primary key id then when you create an issue in your project it will not start with 1 and you can easily guess how many issues exist in the GitLab.
> If you expose the issues table primary key id then when you create an issue in your project it will not start with 1 and you can easily guess how many issues exist in the GitLab.