Cannot handle bare URLs or custom repositories easily?

The current approach relies on "coordinates" to identify actual packages. I see two issues there:

1. there is no provision to reference plain URLs. Common packages such as zlib or openssl release archives are fetched this way (unless the plan would be to have a coordinate "type" and "provider" for each of these)

2. Since URLs are always generated from the coordinates (and in particular the provider) does this mean that if we wanted to support several Maven repositories, there would need to be one "provider" coded for each?

No files, tests, or entry points are mentioned. First clarify the requirements for bare URLs and multiple Maven repositories, then identify the service code that resolves coordinates and generates package URLs; done means both repository cases are supported without requiring a separate provider for every repository.

Written by the indexing model from the issue text.