Yeah, that's one of mine. Documentation is hard!
Unfortunately this plugin does require a modification to core for the time being. Haven't figured out a way to achieve it without that.
I believe the mod is only required if you need to hook the ticket delete process though, if you are after just auto prune of the old ones, it should still work, just will not export them. Hmm, should probably work on that some more eh.
Welcome your input @ramrajone
https://github.com/clonemeagain/osticket-plugin-archiver/issues/2 feel free to open a PR