Represents the package declaration.

#id: id
the unique ID assigned to this fact.

'fullname': atom
package name of this package declaration, as an atom.

E. g.:
packageT(42, 'org.cs3.pl.astvisitor').
packageT(defaultPackage, ' '). (for the default Java package) ← Changed in JT 2.6.3 Previously the PEF for the default package was packageT(null,' ')

Note: packageT does not have the ID of the children in his declaration. packageT has so called unreferenced_children, that means the children referencing the parent, but not the other way around.
The unreferenced_children from packageT are compilationUnitT, see also Program Element Facts for Java AST

 package packaged.de.tests;
 public class tests {
   ...
}

packageT(#Package, 'packaged.de.tests'),
compilationUnitT(#CompilationUnit, #Package, ..., [], #Class),
classT(#Class, #CompilationUnit, 'tests', [#Children]),

ast_node_def('Java',packageT,[
     ast_arg(id,   mult(1,1,no ), id,   [id]), % <-- convention!!!
     ast_arg(name, mult(1,1,no ), attr, [atom])
]).