SourceCred is a subset of provenance focusing on lineage and attribution. As described by the PROV Working Group within W3C,
Provenance is information about entities, activities, and people involved in producing a piece of data or thing, which can be used to form assessments about its quality, reliability or trustworthiness. The PROV Family of Documents defines a model, corresponding serializations and other supporting definitions to enable the inter-operable interchange of provenance information in heterogeneous environments such as the Web.
I ran across PROV while researching a discussion with @mzargham a while back out of which SourceCred’s author/content/event substrate stood out pretty plainly. The parallels between PROV and that substrate also stand out pretty plainly, as @decentralion noted. Something like PROV could be the means of creating a rich, graph-based model of provenance for an arbitrary decentralized project. This provenance graph could be transformed into a canonical contribution graph along the lines proposed in ‘Multiclass Pagerank’.
One particularly interesting aspect of PROV, PROV-O, has a concept of “qualified terms”. Qualified terms provide a means to add attributes describing the influence between resources–specific sets of attributes relevant to different types of decentralized projects. Each type of decentralized project would have a canonical provenance graph. SourceCred would have a canonical contribution graph. Creating a project-type-specific provenance graph and transforming it to a canonical contribution graph would be what plug-ins do. In this way plug-in architecture and design can be standardized across arbitrary project types.
The following illustrates this idea (taken from https://www.w3.org/TR/2013/REC-prov-o-20130430/#qualified-terms-figure). The contribution of one resource to another (black, dotted arrows) can be delineated by or inferred from the underlying provenance (blue, solid arrows). With sufficient detail, perhaps weights of contributions might be modeled from attributes in the qualified terms of the provenance graph.