Weighted percent of files in the project that have a defined owner.
Weighted means that file size relation to other files in the project is taken into account.
It is good, owners help increase development speed, maintain order and reduce number of possible defects in the file.
However, you have to look at Project ownership in conjunction with Bus Factor. Ideally you want a high ownership percentage and a high bus factor value.
It is bad, most likely you will have a lower development speed and a higher risk of defects in the project.