Can anything be done?

I have floating spans which require some content if they're width is
to be respected. In case the value-of is "", then I'd like it to fall
back by having an ¢ after it, but its appearing as a junk
character.

Alternatively use an output encoding of US-ASCII in your transform to
force the serializer to output the character reference instead of the
character itself.

The "junk" you can see is the first byte in the two byte UTF-8
sequence - the first byte tells the reader there are two bytes, the
second byte in combination with the first is the character.

cheers
andrew