2.1.5 [ISO32000-1] Section 188.8.131.52, Absolute and Relative File Specifications
The specification states:
A simple file specification that begins with a SOLIDUS shall be an absolute file specification. … A file specification that does not begin with a SOLIDUS shall be a relative file specification giving the location of the file relative to that of the PDF file containing it.
Absolute and relative file specifications are not supported.