It adds lemons to Minecraft. It's that simple. Lemon trees generate in tropical biomes and drop lemons. Lemons can be used to craft food and "other" items. The lemons are sour though so it will take longer to eat after eating a lemon and you'll go a little blind. Also there are explosives.
A lemon.
When life gives you lemons.
All the fruit, in a juice.
Le legendary lemon launcher.
A really big lemon.
The malleability of leather combined with the toughness (magic) of lemon rind.
Not lemonade.
A pineapple!?
Lemon leather armor set with and without silence armor trim.
The toll testing the lemon mod has had on the landscape.
A field of pineapples.
A house made of lemon.
A real lemon tree out in the wild!
The top of the creative mode tab for the lemon mod.