Please note that you only get syntax highlighting with this extension. You do not get the full Biml or .NET intellisense, the BimlScript preview pane, or the ability to generate SSIS packages from Biml. For those things, you will still need BimlExpress for Visual Studio.
However! If you simply want to view your Biml files in a lightweight editor, the Biml Support extension works beautifully
It’s not full support, but it’s something.