It’s a destructuring assignment. Specifically, an object destructuring assignment.
It might help to see it rewritten in a more verbose way.
const abc = Object.abc;
const def = Object.def;
It’s a shorthand way to initialise variables from object properties.
const name = app.name;
const version = app.version;
const type = app.type;
// Can be rewritten as:
const { name, version, type } = app;
You can do the same kind of thing with arrays, too.
const a = items[0];
const b = items[1];
const c = items[2];
// Can be written as:
const [a, b, c] = items;