Most of the work moved the package ecosystem as the standard library shrank with many of the things in there moving to separate packages (for example, even the package manager is a separate package: https://github.com/JuliaLang/Pkg.jl). The result of this is that what you now see in Julialang/julia is mostly compiler work (and some tweaks to Base things like linear algebra overloads). With that said, it's quite an actively developed compiler!