. . and a preservative if to be sold fresh. They do not stretch. The way I buy fresh ones is sheets, coated with oil and rolled into cylindars. You slice the cylindars any width you want and they should unroll while cooking.

These must be used within a day or two because they can't be refrigerated - they'll stiffen and be nearly impossible to unroll even if heated above room temperature. Big fight in Los Angeles county between Chinese restaurants and health department over this characteristic of rice flour - Chineese eventually won a dispensation for rice noodles and rice cakes.

Rice noodles have no stretch (no gluten) but narrow dried ones possibly can be extruded rather than cut in an industrial environment. Wider dried ones are definitely cut.