What is the meaning of the narrators' saying "mursal jayyid" (well-transmitted mursal) in judging a Hadith?

The mursal is what a Tabi'i attributed to the Prophet, peace and blessings be upon him, as Al-Hafiz Al-Iraqi mentioned in his Alfiyyah. An example of this is the aforementioned hadith that Abu Qilabah, who is from the Tabi'in, attributed. The description "good mursal" means that its chain of narration up to the Tabi'i who transmitted it is good.