Struct Product 

pub struct Product {
    pub id: &'static str,
    pub extension: &'static str,
    pub format: &'static str,
    pub icon: &'static [u8],
}

What an application tells the shell about itself.

The identifiers are not translated: a desktop entry, a window class and a file extension are the same in every language.

Fields

id: &'static str

The binary’s name, which is also the .desktop entry’s basename and the Wayland application id. The compositor matches the three to find the window’s icon, so they have to agree.

extension: &'static str

The file extension the application opens.

format: &'static str

What the file dialog and the empty window call that kind of file.

The English, which is the message id: it is looked up through t where it is shown, because a Product is built before run puts a catalogue in force and a translation looked up here would be the English every time.

icon: &'static [u8]

The application’s icon directory, for the one platform with no other way to give a window its icon.

Windows takes a window’s icon from a resource compiled into the executable, and there is no resource compiler in this build, so the file travels in the binary instead. Empty everywhere else, and empty in a build made from a published crate, where the file is not there to stage: see each application’s build.rs.