Using maxlookbehind would show "xx123a", which is definitely confusing, in my opinion, though thosewould be the characters you have to retain for the next match.
We takes into consideration that main application can't always calculate absolutly optimal length of keeped string. But suggested behaviour helps main application to do it more optimal than now. Best regards. --## List details at https://lists.exim.org/mailman/listinfo/pcre-dev
