I had a comment in IBModule near asset catalogs, stating:

// We only return one artifact, as this is a little complicated...
// actool takes an output *directory*, and in this directory it will
// potentially output "Assets.car" and/or one or more additional files.
// We can discover which files were written in an easily parseable manner
// through use of --output-format xml1, but we have a chicken and egg problem
// in that we only gain that information *after* running the compilation, so
// if we want to know in advance which artifacts are generated we have to run
// the compilation twice which probably isn't worth it.

Those "one or more additional files" MUST be able to be installed with the installation mechanism, but since they aren't tagged, as we have no way of knowing their names in advance, they don't get installed with the application bundle, and we have a serious problem implementing any tool that works this way.

I don't know what the best way to implement this is, but I need some way to add file tags to the list of files in assetcatalog_generated_info.plist after the Rule's prepare script has been run.

Maybe a Rule that takes the assetcatalog_generated_info.plist as input and calls some JS API to add file tags to the resulting files?