These are popcorn nugs, which are also known as larf cannabis. Because they were unable to fully develop due to overshading, overheating, crowding, or fewer resources, these smaller buds also don’t produce as many trichomes as their higher up brethren.
Most cultivators try to trim off or prevent popcorn buds from growing, since they’re less valuable and take resources and energy away from the top colas. However, nearly every plant will produce at least a couple branches of popcorn buds and growers are always seeking out ways to maximize their return on investment. Most cultivators will harvest the popcorn buds, package them, and sell them at a discount to shops, who pass that lower price onto the consumer. Anything smaller than popcorn buds will be gathered as trim to be processed into concentrates or edibles.