If C<FILE> does not start with C</>, C<./>, or C<../>, it is treated
as relative to the C<DESTINATION> directory. If only C<--manifest=>
is specified where C<FILE> is an empty string (C<"">), then C<manifest.js.gz>
If C<FILE> does not start with C</>, C<./>, or C<../>, it is treated
as relative to the C<DESTINATION> directory. If only C<--manifest=>
is specified where C<FILE> is an empty string (C<"">), then C<manifest.js.gz>