articleThreads
Article threads (/Threads). Each thread is a reading-order sequence of bead rectangles on pages — used by readers to jump between columns in a multi-column layout. Empty list when the catalog has no /Threads.
Article threads (/Threads). Each thread is a reading-order sequence of bead rectangles on pages — used by readers to jump between columns in a multi-column layout. Empty list when the catalog has no /Threads.