There are good April’s fools jokes and there is this. Some things you just don’t joke about.

I’m still of the opinion, that your GUI sucks if it needs documentation.

Just don’t bring any device to a protest if you consider bringing a burner device.

Something like that should do it:

i = ~((~i + 1) + ~0) + 1

The fragment of a URL is not sent to the server, so that’s where such platforms usually store the key. That’s also the way cryptpad does it. You can thus share the URL and with it the key.

Of course, you still need to trust the platform. The sourcecode link at the bottom of the page links to https://github.com/timvisee/send who forked from mozilla/send and links back to the web page.