Features

Here's a list of all documented (and sometimes undocumented) features that I can remember: 

 

 [Full list of events] 

 Editing Recipes 

 Editing Tags 

 Adding New Items 

 Adding New Blocks 

 Default Options 

 Changing Window Title and Icon 

 Changing Mod Display Names 

 Loading Assets and Data 

 Modify Items 

 Modify Blocks 

 Adding Fluids 

 Worldgen 

 Chat event 

 Block placement event 

 Item right-click event 

 And a bunch more that I forgot...