Domains (urls) are found within a set of article pages. They are matched against editor-curated lists of "perennial" reliable and unreliable sources. Sources may be generally good, in context, or generally bad, in context, but they must be evaluated on a case-by-case basis. Reports and alerts are tools to investigate rather than automatic reasons to promote or remove a source.
This page can help you find sources to use and to keep track of the use of sources throughout Wikipedia. This page includes bot-generated feeds and human-curated lists.