Where is the path `@v#.#` and `@stdlib`?

When I type LOAD_PATH I get

3-element Array{String,1}:

I read in the environment variable documentation that

If the variable is set to @. then Julia tries to find a project directory that contains Project.toml or JuliaProject.toml file from the current directory and its parents.

So the meaning of @ is clear. But what about @v#.# and @stdlib. What do they refer to?

Is there a function to expand these paths into full paths?

It’s been asked before What are the symbols in LOAD_PATH?