Issue 515

[MarcinGladkowski]

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

1. Does your submission pass tests?
2. Have you lint your code locally prior to submission?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

Hi!

Based on doc: https://getcomposer.org/doc/04-schema.md#type there are possible several types of packages. I think the easiest solution is to check location of source url with fallback to main url.
Would you check it @icanhazstring ?

[icanhazstring]

Looks good. Thank you 💪