The name field of a member header holds 16 bytes, with a slash at the end of the name. Names longer than 15 characters go in a member named //, right after the symbol index. Its data is a run of names, each ending with a slash and a newline.
A member whose name is too long writes a slash and a decimal number, such as /42. The number is an offset into the data of the // member, and the name runs to the next slash and newline.