After reading some of the replies, I have got to ask, what is going through your mind? Do you really think pushing notifications about donations to users is a good solution? Trials? Licenses? Of course solely relying on donations isn't enough, but you can't convince people who don't want to donate to do so. If GrapheneOS wants to generate more revenue, it should offer more options than just donating monies. Maybe selling merchandise could work, but the real solution is partnering with an OEM and selling devices with GrapheneOS that aren't like the crap newer Pixels that come with a barely functioning Samsung modem, easily broken, overheat, have no 3.5mm jack, a bulky design with a huge camera that allows it to slides off wherever it wants to, no easily replacable batteries, and a badly placed front camera. It could also work on bug bounties, and not let the $70k SIM vulnerability incident happen again, but that's not the real solution that is needed in the end.