brother host based printing (HBP)

[thufir]

I received a "pdf" by e-mail, which appears to be using Brother Host 
Based printing, based on:


thufir at dur:~/Documents$ 
thufir at dur:~/Documents$ pdfinfo mystery.pdf 
Syntax Warning: May not be a PDF file (continuing anyway)
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Couldn't read xref table
thufir at dur:~/Documents$ 
thufir at dur:~/Documents$ evince mystery.pdf 
Syntax Warning: May not be a PDF file (continuing anyway)
Syntax Error: Couldn't find trailer dictionary
Syntax Error: Couldn't read xref table
thufir at dur:~/Documents$ 
thufir at dur:~/Documents$ head mystery.pdf -n 2
%-12345X at PJL
@PJL ENTER LANGUAGE = HBP
thufir at dur:~/Documents$ 


I can't really make heads or tails of this.  Can I convert this to pdf 
somehow?  I downloaded the only documentation I could find:

http://hbp-for-brother.sourceforge.net/

but the readme wasn't terribly informative.  What is host based 
printing?  I would like to read the data, or, at least, "print" to a pdf.  
How can I do so?



thanks,

thufir