Having done this type of work before for a legitimate purpose, it is almost certainly a python or perl script with a nice library in front of it that makes it easy to follow links.
wget is too brittle, not extensible enough, and not as maintainable as a nice python script.
I believe Manning actually used Windows batch scripting to automate wget, or so the government alleged from forensics at the trial. (I observed a couple days of the trial).
Manning did not have the tech skills of Snowden though, she wasn't neccesarily doing things in the most effective or elegant ways, but it worked.
wget is too brittle, not extensible enough, and not as maintainable as a nice python script.