what are the categories of the extractor?
EXTRACT - traditional extractor, typically adds metadata or derived outputs to the triggering file/dataset; default
CONVERT - primary function is to convert file(s) from source format to another format, combine files, etc.
ARCHIVE - eligible for triggering using Archive/Unarchive buttons, should expect one of those two parameters
PUBLISH - intended to publish files or datasets to external repositories
WORKFLOW - primarily manages workflows, submits external jobs, triggers other extractors, e.g. extractors-rulechecker
SILENT - if in this category, extractor will not send common status messages (e.g. STARTED)