Is the Package-List field necessary for uploads ?

[Charles Plessy <plessy@debian.org>]

Dear FTP team and everybody,

we are documenting in the Policy the Package-List field of the Debian source
control files.

  Multiline field listing all the packages that can be built from
  the source package.  The first line of the field value is empty.
  Each one of the next lines describe one binary package, by listing
  its name, type, section and priority separated by spaces.  There
  are two possible package types: binary package (<tt>deb</tt>) or
  micro binary package (<tt>udeb</tt>).

I do not know if this field should be marked mandatory, recommended or
optional.  Is this field is strictly necessary for uploads ?

Have a nice Sunday,

-- 
Charles Plessy
Tsurumi, Kanagawa, Japan