Is it possible, to make a snap not downloadable when it was initially installed?
If not, what information is in the downloaded snap? Can the content be read or is it possible to keep confidential information inside a snap confidential even after downloading?
Firstly the downloaded app only includes the snap container that is used for installing the app again. So only the base function and files also delivered when downloading from our server and no information probably gathered while the usage.
You can check this on your own by opening the app and snap as it is similar to a zip archive.
The answer of confidential code is depending on the programming language chosen: