[vhhn]

I was surprised when VSCode snap told me that I should start using different snap to install new versions if VSCode and that my settings would be kept. And it did. So there is some way to respect users settings across snaps at least

[Lorkki]

The official VS Code snap is unconfined, ie. it only uses snap for package management without the sandbox. This means it can access the settings stored in your home directory just the same as if it was installed through apt.

Snaps with strict confinement can also ask for home directory access as a specific permission.

[redmorphium]

Possibly how it's done: the settings are stored in a config directory, like ~/.vscode or something.

For instance, my neovim AppImage works this way (it still reads ~/.config/nvim/init.vim like regular neovim).