in MQ/42/support/mq42_0002en.pdf, there were a number of broken links because there were typos in the links. Tried to edit in text editor, but that borked file. Then opened file in Adobe Acrobat Pro, and it wouldn't let me edit the existing links, but would let me create a new link object on top of each existing on, which is what I did. Not sure if that stupidity is due to PDF format or my specific combination of editor version and data file version.