Application identifiers

It is sometimes useful for an application to be able to identify itself outside of a single wayland connection. For example, to get access to an otherwise privileged protocol (e.g. ext-layer-shell) via some out-of-band mechanism (e.g. a portal.) Such an identifier should be non-guessable and generated by the compositor. The compositor might persist such identifiers or not. The compositor might allow users to manage such identifiers and their associated permissions.

A simple protocol that allows a application

• to generate a new identifier
• set an existing identifier

would be sufficient for this with permission/state management left to other protocols/out of band.

This is similar to !18 but without the focus on window management. E.g. a screenshot application could use this protocol to take screenshots (via ext-screencopy) without ever creating any window.