I personally think that Fossil is a good example that's extant and used in serious projects. There's that one called pijul which also looks good in theory, but

I personally think that Fossil is a good example that's extant and used in serious projects. There's that one called pijul which also looks good in theory, but I haven't worked with it. I think version control in general is a little broken before you even get to the software level, but those are two projects tackling some of the problems. And Fossil, I think, is more suited to the scale most people operate on.