GitLab Pages is the same as GitHub pages, except you can keep a pages site's source private without paying.

On GitHub, you can only have a GitHub Pages site and keep the source repo private if you pay for pro.

On GitLab, you can have a private repo while keeping the pages site associated with it public

Same as GitHub, GitLab pages do not support any server side code, and only host static files. This means it is not possible to get any identifying information from it.