Cut-down snapcraft.yaml for hand-repacking a Firefox Try build

snapcraft.yaml

name: firefox
version: 65.0a1-20181114194420
summary: Mozilla Firefox web browser
description:  Firefox is a powerful, extensible web browser with support for modern web application technologies.
confinement: strict
grade: stable

apps:
  firefox:
    command: desktop-launch $SNAP/firefox
    environment:
      DISABLE_WAYLAND: 1
      HOME: "$SNAP_USER_COMMON"
    plugs:
      - avahi-observe
      - browser-sandbox
      - camera
      - cups-control
      - desktop
      - desktop-legacy
      - gsettings
      - home
      - network
      - network-observe
      - opengl
      - pulseaudio
      - removable-media
      - screen-inhibit-control
      - unity7
      - upower-observe
      - x11

plugs:
  browser-sandbox:
    interface: browser-support
    allow-sandbox: true

parts:
  desktop-gtk3:
    source-commit: 6a600b00773e8e4624aa12ee1f8e013ba9f2fc03
  firefox:
    plugin: dump
    source: source
    stage-packages:
      - libxt6
      - libdbus-glib-1-2
      - libasound2
      - libpulse0
      - libgl1-mesa-dri
      - libgl1-mesa-glx
      - libmirclient9
      - desktop-file-utils
      - ffmpeg
      - libc-bin
      - locales-all
    after: [desktop-gtk3]