Otniel was the first Biblical judge after Joshua's death. Jews are allowed to visit only a few times a year, and one of those days is Tisha B'Av.
The Jerusalem Post reported on one such pilgrimage in 2019.
One 19th century visitor to the tomb was Israel Joseph Benjamin, a Jew who traveled the world in search of the ten lost tribes of Israel. His book looks really interesting, and I hope to have more posts about it, but he mentions the gravesite:
Likewise outside the city (of Hebron) towards the south in a vineyard, which was purchased by the Jews, are the graves of the father of King David and of the first Judge, Othnieli the son of Kinah (sic.)Benjamin, whose pen-name is based on famed Jewish explorer Benjamin of Tudela, also mentions the tomb of Abner, also in Hebron, which can only be visited by Jews for ten days a year.
