XUSEQP is a command that is used to request that 
attachments in replies to you should be encoded using
the MIME Quoted Printable encoding.

This command is present for those users who need 
quoted printable encoding as opposed to Base 64

Example:
XUSEQP
http://www.ictp.trieste.it

The above example would send the modifed HTML page
to you using the Quoted Printable Encoding, instead
of base 64 encoding.


NOTES:
The Quoted Printable Encoding does not handle
binary files very well. Base 64 is better for
binary files.