It's not a scientific metric; I did preface this by saying that "bloat" is a subjective term. But LOC of the codebase is a pretty good rule-of-thumb metric; I'm not pretending any more credibility than that. It's not hard evidence, but it is an indicator (and I chose the word carefully) that the codebase may be trying to do more than it ought to. It is an indicator in the same way that fatigue and a rash around your joints are indicators that you have strep throat, but the evidence would be the presence of some strain of streptococcus in your blood. There's no line of code that one can point to and say "Hey, that conclusively proves bloat."