This is a WordPress Multisite installation with some adaptations and limitations.
It is not possible to install themes or plugins. The URL of the blog will be https://blogg.usn.no/<blogname>/
The wordpress installation will be updated when needed. This includes the core wordpress files, the plugins, the themes and the translations. When this happens, users can experience some changes in how things work, but the main functionality (publishing posts and pages) should remain.