Tooltips+

When an item has more saturation than hunger, the hunger is overlayed on top, like so:

When an item has less or equal saturation than hunger, the saturation is overlayed on top, like so:

If that didn't make sense, here's a chart:

Burn amount is self-explanatory: it's the number of items this item can smelt when used as fuel.

Compost chance shows the percentage chance an item has to fill a layer in a composter.

If you have any suggestions for additional tooltip information, leave them below!