I introduced and use the usePreTriggers parameter only for debugging/testing of the packer/unpacker chain with current available data samples from P5 (which don't have CLCT pre-Triggers digis available). So I'm not sure if it should be made tracked for the final version.
Regarding new theFormatVersion parameter I don't really know for now how upstream modules, which are going to use the CSC packer would select, which version of data format to use for packing and which config files it would affect. So by default it is set to 2005 version. If it passes initial backward compatibility tests with 2005 format and it would be clear in what scenarios and how it will be used with new data format, then it would make sense to make it tracked.
Thanks for the reference to ::fillDescriptions method. Let me try to add it later.