At this point I have a script which, given a current GAV and a target branch (incl. PR!), will dig through Artifactory and GitHub metadata to determine the best available update (whether that be a JEP-305-based incremental version, or simply from MRP). The next step is to embed this in a tool which takes a metadata file and actually edits it to select updates for one or more components.
Since I am struggling to find an example of a YAML config file already using incremental versions which could be used as a test bed, and I left some comments in the BOM JEP draft about a suggested modification to the format that would be more amenable to this tool, I am going to start with a Maven POM processor that could be used for
JENKINS-47498 as well as simple chained pull requests.