Functions like notifyBugsnag will do nothing with exceptions that pass
this predicate. N.B. Something lower-level, like reportError won't be
aware of this.
A CodeIndex built at compile-time from project sources
If set, this will be used to update StackFrames to include lines of
source code context as read out of this value. N.B. using this means
loading and keeping the source code for the entire project in memory.