Google copied the declaring source code from the 37 Java API packages verbatim, inserting that code into parts of its Android software. In doing so, Google copied the elaborately organized taxonomy of all the names of methods, classes, interfaces, and packages — the "overall system of organized names — covering 37 packages, with over six hundred classes, with over six thousand methods." Copyrightability Decision, 872 F.Supp.2d at 999. The parties and district court referred to this taxonomy of expressions as the "structure, sequence, and organization" or "SSO" of the 37 packages.

The Baker ruling is specifically addressed in that one, and they call out exactly how it is relevant to Oracle v. Google: The Baker precedent says that the parts of a design that are strictly essential to its function are not copyrightable. But the parts that involve some art - such as - according to this opinion - the taxonomy introduced in a package structure - are copyrightable.

In other words, you can think of SSO as shorthand for, "The things that aren't covered by the Baker precedent."

We also have, in the same opinion:

When assessing whether the non-literal elements of a computer program constitute protectable expression, the Ninth Circuit has endorsed an "abstraction-filtration-comparison" test formulated by the Second Circuit and expressly adopted by several other circuits. ... This test rejects the notion that anything that performs a function is necessarily uncopyrightable.

(Disclaimer: This is not meant to imply that I think that Judge O'Malley's 2014 opinion is the final word on the case. I'm just picking some highlights from an opinion on this case that might shed some light on how the Courts are approaching the issue.)

(https://www.leagle.com/decision/infco20140509135)