[$] Graphene OS: a security-enhanced Android build

People tend to put a lot of trust into their phones. Those devices have
access to no end of sensitive data about our lives — our movements,
finances, communications, and more — so phones belonging to even relatively
low-profile people can be high-value targets. Android devices run free
software, at least at some levels, so it should be possible to ensure that
they are working in their owners' interests. Off-the-shelf Android
installations tend to fall short of that goal. The GrapheneOS Android rebuild is an attempt
to improve on that situation.