Free modules in the Part I interface

Warning 8.5.5. This is a special case of the free-module construction from Subsection 19.1.2. There one allows modules of the form \(R \otimes X\) for an arbitrary spectrum \(X\); here \(X = \bigoplus _{i \in I} \S \) is required to be a coproduct of unshifted copies of the sphere spectrum.