Mishnah tractate Yoma names a site east of Jerusalem and describes a cliff, a measured route and a series of stations along it, but the name is spelled differently across the manuscript traditions and no identification on the ground has been established. No candidate site has a scholarly case mounted for it, so this is an unfilled gap rather than a contested identification.
What would resolve this A survey along the plausible routes east of Jerusalem for a cliff matching the described distance, together with the remains of the staged booths, could produce a candidate. A firmer reading of the place name from the better manuscript traditions would narrow the search before any fieldwork.
OpenHistorical geography of Judaea, rabbinic manuscript studies, field archaeologyAnonymous (rabbinic compilers), The Mishnah