Major Specification states:
Content Warrant
The proportion of the product defined that is from non-fossil fuel sources, including but not limited to "hydroelectric", "nuclear", "solar", and "wind".
Source Warrant
The product source. In aggregate may be the same as a Content Warrant.
Schema states:
<xs:documentation>A content warrant consists of assertions about where energy originated. </xs:documentation>
<xs:documentation>A source warrant consists of assertions about through what proces energy originated. </xs:documentation>
A few problems:
1. it appears there is no method to identify the "content" that is fossil based, since the description of "source" states "in aggregate may be the same as a Content Warrant" which one might interpret as meaning it is all non-fossil.
2. it is unclear how the schema documentation for content "about where energy originated" is aligned with the spec description
3. it is unclear how "about through what proces [sic] energy originated" actually means (typo does not in this case detract from apparent meaning)
4. it is unclear if the "where energy originated" in the content warrant refers to a physical location (a typical "where" answer) or to a fuel source, as its description implies.