I want to use Babylonjs purely client side. I know I can use the CDN for the client side scripts but I often work offline so I need the .js locally in my project and ideally with some typescript d.ts files. The V5.0 help pages I have been looking through today seem to show only CDN or npm/webpack solutions.
Is there somewhere I can download what I want?
You can download all files needed from the CDN. It is just serving the same files you can host on your own.
Otherwise, you can clone the repository and build yourself, or download the entire snapshot from our releases:
Releases · BabylonJS/Babylon.js (github.com)
I have created a babylon project generator if you want a full developer experience locally.
npm init babylon@latest
it will generate a project that you can open in VS Code and you have everything already configured.