I used Unity Hub 2.0.2 to install the latest stable Unity release (2019.1.8f1). In the "Add modules to your install" section I had three modules selected: WebGL Build Support, Windows Build Support (IL2CPP) and Documentation. Once the installation was complete, I used the Hub to create a new project (using the 2D template) and tried to build it for WebGL target, but it looked like WebGL support didn't install at all. The WebGL section in the Build Settings window had only the "No WebGL module loaded" message and "Open Download Page" button, which led me to download the WebGL build support as a separate file. I also checked the installation directory and it seems the Documentation wasn't downloaded either. The Windows build support did install correctly. I tried installing Unity (from the Hub) on another machine, on which I also checked the "Android Build Support", but again only the Windows Build support was installed.