How to edit the ivy.xml file that sbt produces for publishLocal (or publish)

sbt seems to create an ivy.xml file, along with a pom file, during a publishLocal, even though ThisBuild / publishMavenStyle := true. It doesn't seem to be a problem with publish, because the ivy.xml file never makes it to the server. An sbt consumer of the locally published snapshot seems to use the ivy.xml file rather than the pom file. I've edited the pom file that gets produced using ThisBuild / pomPostProcess := ??? and would like to edit the ivy.xml similarly. We have access to ivySbt (and lots of other things), but I don't see how to edit the string or the XML nodes of the ivy file. Can anyone show how that might be done?