This is a harvestable tree that produces oranges, which can be used as a cooking ingredient, eaten raw, or turned into juice with this juice blender (recent update).
The tree is actually the same model as the lemon tree, so not very exciting. The screenshot is taken with the texture override from this mod (Garden Variety)
The oranges are a custom ingredient, tagged as Fruit, so they can be used for any recipe that requires fruit. To buy oranges from the fridge, use this mod (graycurse, Shop from Fridge, currently in Feedback at mts), or turn on debug mode and search for “Orange” to buy them from the catalogue.
(Yes, I could make a custom seed packet, but if I did that, I would move it to the fridge anyway (since the game doesn’t give you seeds, it gives you fruits), and also make it so that you can actually pick what you want to purchase .. in other words I would end up doing the same thing that graycurse has already done. Which would be a little pointless.)
US English, Traditional Chinese (wuccwzt), Dutch (ElenaInTheSims), French (Damabiah), German (pbox), Italian (Ele88), European Portuguese (simshout), Brazilian Portuguese (daniel1217), Russian (igor97), Spanish (Naus Allien), Polish (Piesek64).
Strings, if anyone wants to contribute additional translations:
 0xFF7D2896: A tree that produces oranges.\n\nmodthesims.info/members/plasticbox
 0xA50EEFA7: Orange
 0x88FE283D: A tasty orange.\n\nmodthesims.info/members/plasticbox
A tutorial on how to edit the strings in a mod is here.
Tree: no mesh included
blender, Paint.net, TSRW/Milkshape, Notepad++, s4pe.