List of referring domains that Adobe considers search engines

Is there a publicly available list of which referring domains Adobe considers to be search engines? The "Search Engine - Natural" dimension provides a friendly name rather than the referring domain, and applying a segment in which "Search Engine-Natural" exists to Referring Domains is resulting in a lot of domains that are definitely not search engines. I can use a segment in which "Referrer Type" equals "Search Engines", which works better, but was curious as to whether there was an official list.