It looks as if thise methods haven’t been documented in the source
files (not sure why). The reason they’re pulling up the
singleton_method_undefined is a quirk of the way the source is
organized: it has six or seven Ruby methods all implemented by the same
C method.
I’ll look in to this, but is anyone in the doc team feels like adding
the documentation, please fel free: I won’t be able to get to this
until next week.