Tape specs and descriptions tend to be a little mysterious (e.g. “adhesion to steel”), and the description of Shurtape 724 includes one of those terms.
The term is “flatback”.
What this refers to is the smooth “flat” finish for the non-adhesive side of the tape. The most popular paper tape is masking tape, and it has a “creped” textured finish as opposed to being smooth.
Being “flatback” means that 724 paper tape has a smooth surface for writing or printing. This is one of the features that makes it so compatible with the Sharpie Marker every sound or lighting tech has in his pocket.