How to see all installed packages? + a few other `Pkg` related questions

@kristoffer.carlsson thank you very much, but when I do Pkg.dependencies() I get packages I have not installed on the current version of Julia (1.8.5 just today). It lists packages I’ve installed in the past. I don’t know how to write an up to date replacement for the following. Can you help? Or maybe there is a link somewhere showing how to do this?

# Check if BenchmarkTools is installed
if !("BenchmarkTools" in keys(Pkg.installed()))
Pkg.add("BenchmarkTools")
end