arc_summary to be able to show only altered tunables,spl

Describe the feature would like to see added to OpenZFS

arc_summary -s tunables/spl currently shows all values I wish I was able to quickly see only the modified values. By passing a new supplementary argument, arc_summary would omit showing tunables that are left at their default values

How will this feature improve OpenZFS?

Easier and faster identification of alterations in arc_summary tunables section output

Additional context

to help arc_summary automate obtaining default values instead of hardcoding them, modinfo -p for zfs,spl,icp and zcommon should also display default values, not just the description, in a parsable form (an identifiable pattern to extract the default value)