I have deployed an app from a private repository, and selected the option ‘This app is visible to anyone with the link’.
However, I’m not what this means for the source code. If someone gets a hold of the link, can they also see my python code (e.g. through developer tools), or can they only see the user interface?
No, if your code repo is private, then people cannot see the source code, irrespective if your app is available to the world. You can validate this by right-clicking in the browser and selecting ‘view source’; all you’ll see is obfuscated JavaScript, no Python code.