refers to a LaTeX document class file, it is typically not a standalone file for public download like standard CTAN packages (e.g., elsarticle.cls
rather than distributed as a standalone package on repositories like CTAN. Integrated Use: Users normally access it by logging into the Neptune - TeXFolio portal Documentation: neptune.cls download
If you are an author or editor working with a journal that uses TeXFolio, you do not typically download the .cls file manually. Instead, you interact with it through the Neptune web interface: refers to a LaTeX document class file, it
Alternatives if you can’t find Neptune I am releasing the neptune
Because Neptune is primarily a cloud-based Software as a Service (SaaS) tool, the neptune.cls file is typically integrated directly into the system's environment rather than being a standalone package on public repositories like CTAN.
I am releasing the neptune.cls class file today.