What is the design number of this brick?
That's 98613c01 - Hero Factory Arm / Leg Extender with Ball Joint and Ball Socket on BrickLink.

LEGO call this item Ball Cup High Friction W. Rubber and use 74261 (design ID) and 6106472 (Element number) for latest sets.

LEGO doesn't always have full list of parts within a set as this depends on parts availability (maybe some other reasons too). You would get much better set inventory on BrickLink. Check your set - 31058 on BrickLink, where you can find the part you are looking to identify.