Dropbox publishes its Linux client for x86_64 only, so on AArch64 the
dropbox package installs that same client and runs it under box64. Only
dropboxd changes: it execs the client through box64, and /usr/bin/dropbox
points at it, so the systemd units and `dropbox-cli start` both go through
the emulator. The x86_64 package is unchanged.
dropbox-cli is a Python script and becomes arch=any.
David Heinemeier Hansson