Codeigniter download install web vs Composer

Hello

Just wondering about the difference between download and install the archive from
https://codeigniter.com/download

vs installing it through

Code:

composer create-project CodeIgniter/framework my-ci-app

I mean

why with the composer method I find a vendors subdir with so many vendors subfolders?

with composer I tried both the packages

Code:

CodeIgniter/framework

Code:

bcit-ci/framework

with either, I find the vendor subdir with so many folders while the web archive doesn't have the vendors subdir

Is it because the two composer packages are unofficial?

Thank you for explaining the difference