perlexperiment points at perlguts, referencing "internal functions with M flag" perlguts says: M This function is part of the experimental development API, and may change or disappear without notice. I don't see any reason to call this out specifically as a line item in perlexperiment. autodoc suggests that any function flagged M or x gets this text added: NOTE: this function is experimental and may change or be removed without notice. There are by a very rough count, 90 such functions. I don't think it is useful to document them all in perlexperiment, either. (I wonder how useful the x and M flags are in practice? That's probably a separate issue.) Unless someone provides a good objection, I will remove this piece of perlexperiment. -- rjbs