With relay.tools, you don't even need to download, as it reads straight from the relays.
Discussion
That's why I encourage people install Citrine, as it's a great local storage for their publications. Then they can read them offline.
yes and relaytools-android keeps all loaded event in memory, so if you task switch without killing it, well, it's like a big in-memory cache. profiles and relay lists are cached to disk, the rest is per relay on switch or resume.