Given the work being done by Sasa Zivkov to translate messages coming out of the JGit library, we shouldn't be doing this.

If the caller needs to know this type of exception from other exceptions, this needs to be a custom exception type that they can catch with a try-catch block.  If the caller shouldn't need to handle this exception differently from other exceptions we throw, this message should simply be private to the package, with possibly a translation for presentation.