micro is a terminal editor with nothing to learn first: the arrow keys
move, typing types, Ctrl-S saves, and the mouse works. It is one binary,
with syntax highlighting, multiple cursors and undo already inside it.
The demo opens a small Node service. Type anywhere, press Ctrl-F to
search, or double-click a word and press Alt-N to put a cursor on the
next copy of it — then type once and change them all. Ctrl-S saves,
Ctrl-G opens the help, Ctrl-Q quits. The VM is private to your browser
tab; nothing you type leaves it.