instance
Keeps a desktop app to one instance, handing later launches to the one running.
An app has it by having @crossbind/core-app-host, which lists it as a dependency: there is nothing to install or list.
Use
A later launch brings the running app's window to the front and hands it its arguments.
Options
app.singleInstance: true keeps the app to one instance. On Windows and Linux an app with URL schemes or file types has it without asking, as a link or a file starts the app again there; false turns that off.
Platforms
macOS, Linux and Windows. A phone keeps every app to one instance itself.
Replace or leave out
It holds the role instance. An extension that gives replaces: 'instance' takes it; app: { without: ['instance'] } in crossbind.config.js leaves it out. Leaving it out while app.singleInstance is true stops the build. The guide shows how, and extensions.md what a replacement answers.
app.md has how a launch is handed over.