Hi, I read this in Julia doc (https://docs.julialang.org/en/v1/manual/types/#UnionAll-Types-1)

```
julia> const T1 = Array{Array{T,1} where T, 1}
Array{Array{T,1} where T,1}
```

- What is the meaning of
`const`

in this context?- eg I built a variable like here below, and it is not very constant?

```
julia> aa=T1([[2.0],[6::Int64],["bof"]])
3-element Array{Array{T,1} where T,1}:
[2.0]
[6]
["bof"]
julia> aa[2]=[1];
julia> aa
3-element Array{Array{T,1} where T,1}:
[2.0]
[1]
["bof"]
```

I also tried this (without the `const`

) like this: `T2 = Array{Array{T,1} where T, 1} `

the difference with `T1`

is not clear to me.

- Where is the documentation for this use of
`const`

(ie in a type declaration context)?

Thank you!