Thanks, this is very helpful! WebKitGTK 4.1 and GTK3 are both installed, so a missing dependency doesn’t seem to be the cause.
I haven’t identified the exact cause yet, but I’ll investigate it using the diagram and package versions you provided. The application currently catches Mermaid rendering errors and shows the source as a fallback, which is why nothing appeared in the terminal.
Thanks again for taking the time to provide all this information!