Right, mihaim has already posted an explanation to the EF client, but his is incomplete and to be honest, it sucked. Also, it will be better and more truthfull coming from the people that have had the time to use it. Of course i cannot give screenshots of it from myself, since i cannot log onto them anymore. I shall use the screenshots from mihaim in the other topic though. I will only go into detail on the parts that are illegal.
Firstly - There are 2 versions of the EF client, the XELC Light, and the XELC. The XELC Light being the legal version, and the XELC being the illegal version. The XELC version was in time, split into 2 versions, XELC1.e and XELC1.f.
Each client had the EF textures which to most people, looked better than the original textures.
Second screenshot was an old one with textures on
On both XELC clients there was an automixer, this would work by selecting items in the manufacture bar and clicking mix, as long as you have the ingrediants in your inventory it will continue to mix, and eat during this. The mix was slower than making by continious clicks, but it enabled you to reset your fingers and give you the chance to chat in game. Doing anything else in game e.g. moving, taking things from storage or moving something in your inventory will cause it to stop. Occasionally the automixer will also automatically stop, so going afk while mixing would make you even slower to make what you want.
Repeat button: The repeat function at the bottom of the NPC windows allowed you to repeat the last thing you did with the NPC, like spending 1 pp on coordination, you click repeat and it will spend another on coordination. The repeat button on the storage NPC does not work since the storage was updated. Rogue saying in the other post about using it to repeat deposit/withdrawl from storage, that is bull, even if you wanted to withdraw 200 FE instead of 100, you just need to change the quantity in your inventory.
End button: The end button was made to attack the closest animal/monster to you, this does not walk for you, if the monster or animal is too far away, you will have to walk to it yourself. It was ony implemented to help fight little animals and monsters such as rabbits, snakes and fluffy rabbits.
Battle menu: The battle menu was only on the later release of the XELC (XELC1.f). This gave you a button to cast restore, harm and drink a potion, pretty much the quickbar in a new bar. It also had a button to use a teleport ring in your inventory, use a disengage ring and a use damage ring button At the bottom it did have an auto heal and auto drink potion lvl set. This is the main reason users of the EF client decided against using the XELC1.f, because it was TOO illegal. This is how the third EF client version was made, one with only the automix, and one with automix and auto heal.
Tab: The tab button did have bags on map and players on map, The players on map showed only the players in sight of you and the bags on map was mainly buggy, showing tons of bags on map, when there is none (pretty much useless to find bags..).