From Fedora Project Wiki
The Fedora Localization Project - Graphical User Interface
This is a list of the most important (essential) projects. They are either installed by default in Fedora Workstation or widely used. Its purpose is to help translators to correctly prioritize their work.
If you want the most important project, that would be the anaconda installer.
- Linux PAM
- Fedora Media Writer
- selinux (policycoreutils)
If you want to translate Fedora websites, you should start with start.fedoraproject.org and getfedora.org.