Back in september 2022, https://twitter.com/frankdejonge introduced a new https://github.com/laravel/framework/pull/44105 filesystem driver to Laravel. This driver works by extending an existing disk and configuring a prefix, which would be a path to a directory in the extended disk.
For instance, say you have user avatars, contracts and passports.
The reason for that is that most of the time, we no longer use the default disk, so configuring it is not necessary.
Since default no longer use it, we can use the FILESYSTEM_DISK environment variable to configure the base disk for all our scoped disks.