I was reading the source code of Foliate- A Javascript Epub reader and then I came across this

const { Gtk, Gio } = imports.gi
const ngettext = imports.gettext.ngettext
const { mimetypes, readJSON, sepHeaderFunc } = imports.utils
const { EpubViewAnnotation } = imports.epubView
const { EpubCFI } = imports.epubcfi
const { AnnotationRow } = imports.contents

` find foliate on https://github.com/johnfactotum/foliate

Somebody explain me this