mozilla jetpack hello-world https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/tutorials/getting-started-with-cfx.html
edit xpi metadata
load in-page.js
use simple-storage https://addons.mozilla.org/en-US/developers/docs/sdk/latest/modules/sdk/simple-storage.html
play with postMessage between page script and content script https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/guides/content-scripts/communicating-with-other-scripts.html
cfx pxi