One of the nice extras in the Plugin Manager Enhanced V2 is the (debug mode) Edit button that opens the plugin’s source file in a whatever editor is tied to .py extensions. This simplifies inspecting the code.
Also very nice feature is in Kari’s prototype Filter2 gramplets. They scrape all the settings in the Filter gramplet to build a custom filter.
Also, his experimental FilterParams tool makes inspection in the GUI easy. (Particularly since it isn’t like the Gramps Filter Editor that doesn’t let you switch the category silos for the filters.