The web-launched Vision Clients in Ignition are the "runtimes" of the Vision module. You can launch one or more Clients to display the projects you created in the Designer. They run as full applications and feel like a traditional installed Client, without the need to install and manually synchronize projects.
Ignition Clients may look differently on Windows than on Linux. This is because Linux does not have the default Arial font that Windows uses. To have Linux use the same font, it will need to be download. Check out a forum post where a user goes over how to do this: https://forum.inductiveautomation.com/t/java-fonts-and-linux/1112