Comment by martin-t

I was gonna say the last few percent might increase the size disproportionally as the last percent tend to do[0] but looks like boa passes fewer tests (~91%).

This is something I notice in small few-person or one-person projects. They don't have the resources to build complex architectures so the code ends up smaller, cleaner and easier to maintain.

The other way to look at it is that cooperation has an overhead.

[0]: The famous 80:20 rule. Or another claiming that each additional 9 in reliability (and presumably other aspects) takes the same amount of work.