On macOS with a Finnish keyboard layout, $ is typed with Option+4. While
writing this manpage, I made the mistake of holding Option down a little
too long, as I often do, resulting in the keystroke Option+space. This,
instead of typing a space, types U+00A0 (non-breaking space), which
looks identical on my host terminal. Luckily the Serenity terminal
called me out on it, printing out a question mark instead.