Offline Caching от octt

This add-on enables offline caching on any web site or app, even those that aren't developed with this feature in mind, allowing use when Internet isn't available. This works by injecting a dedicated Service Worker on any host you choose via the popup menu, so it has the benefit of using an established and well-tested web technology to do its job. Due to Service Workers limitations, keep in mind that this only works on HTTPS sites and outside of private browsing mode.