There’s something weird and inconsistent going on with how URLs are formatted for different people. It’s really perplexing and annoying: the URLs that some people get in the doc system are broken for other people and vice versa. One of these should hopefully work for everyone:
https://docs.julialang.org/en/latest/stdlib/Pkg
https://docs.julialang.org/en/latest/stdlib/Pkg/
https://docs.julialang.org/en/latest/stdlib/Pkg.html