The trailer contains pointers to the xref table and to key objects contained in the trailer dictionary. It ends with %%EOF to identify end of file.

The trailer begins with the keyword trailer. This is followed by a dictionary. The trailer ends with the keyword startxref on one line, followed by the byte offset to the beginning of the xref keyword on a line, the finally %%EOF on a line.

trailer<<
key1 value1
key2 value2
>>
startxref45678
%%EOF

The dictionary may contain the following entries:

Key	Type	Required?	Descrition
Size	Integer	Required	The total number of entries in the cross-reference table
Root	Dictionary	Required	An indirect reference to the Catalog dictionary for the PDF document
Info	Info	Optional	An indirect reference to the file formats - PDF - information dictionary for the PDF document