De-duplication needs to be explained

[bam80]

Currently, the Docs contain no clear explanation of the de-duplication feature. It only has phrases as:

It also has the advantage of reducing the amount of duplication on users’ machines, since it means that Electron is only saved once on disk.

But it completely confusing, because when you build your project, what you see at first look is the files are just copied! It's not at all intuitive the files would be de-duplicated further. Actually, I personally faced the fact people just consider Flatpak is bad design because they think it duplicates it's content (I was unaware of that too). Thanks @TingPing for the explanation: https://github.com/flathub/com.dosbox.DOSBox/issues/4#issuecomment-438498901

@alexlarsson seem has a good blog post about it: https://blogs.gnome.org/alexl/2017/10/02/on-application-sizes-and-bloat-in-flatpak/

[TingPing]

For the most part it is an implementation detail users/developrs don't need to know. Other than knowing on disk things are stored as efficiently as possible.

[bam80]

@TingPing I don't agree with that. It has huge difference even for users, as I wrote in previous post.

things are stored as efficiently as possible

is not enough and confusing

[mwleeds]

We do have this paragraph in the "Under the Hood" section:

Storing applications in a local OSTree repository has other advantages. For example, it allows files that are stored on disk to be deduplicated, so the same file that belongs to multiple applications (or runtimes) is only stored once.