Sorry for the date mess, I'm in a car and sometimes my homebrew
Raspberry Pi 400/Kindle computer-screen-keyboard breaks  and reboots,
thus resetting the date.

Dialog's coming soon, hopefully ...

And it does what you'd expect it to! Only dictionary search available at
the moment.

This is to prevent things such as sleep mode from printing anything on
the display when the reader is in USB MS.

Really, I could've just checked the battery state to know whether an USB
cable was plugged in...