With the addition of the `backtrace_include_patterns`, I think it would be preferable if the old option was `backtrace_exclude_patterns` rather than `backtrace_clean_patterns` for greater consistency/symmetry.  We can't just rename it, though, but what about making `backtrace_clean_patterns` a deprecated alias to `backtrace_exclude_patterns`?  Then we can remove `backtrace_clean_patterns` in RSpec 3.0.