So there we go! The full L2Tenkai sources and project at the hands of anyone wishing to check it out:
https://github.com/PCasafont/L2T_Server
Feel free to branch it and/or do whatever you like with it.
Some brief description of what's coming in the pack:
Helios client support
Most of the latest features supported, featuring:
New SA system (Ensoul).
Full support of latest Life Stones.
Beauty manager.
Compound system.
Abilities system.
Tons of rewritten modules, featuring:
Skill effects in L2Tenkai are called abnormals, and abnormals can have diverse effects and stat modifiers in them.
Armorsets are in XML and have full support for the dynamic effects they can grant.
Augments system has been completely rewritten. Now you have a big folder with xmls specifying all the effects and a lifeStones xml which tells what effects can each life stone bestow to items.
Spawn system. You can have spawns in the NPCs' data, in different XMLs under the /spawns folder and there's support for dynamic spawn groups (for stuff like night/day mobs, fortress guards, castle...)
Raid boss spawns are now handled in the NPCs' data, you can give NPCs unique spawns with long respawn times which will be stored in the database.
Skill XMLs are much more readable.
Item XMLs are much more readable.
NPC XMLs are much more readable.
Extremelly customizable, with the data_[name of your server] folder, in which you'll be able to override all the data to your liking without touching the original stuff.
All the player classes and skills up to Underground implemented, partially updated to Helios.
All the important items up to Underground implemented, partially updated to Helios.
A huge bunch of custom and retail instances/bosses/scripts, most of which I'd honestly rewrite, but most of them work most of the time ::)
Classic-ready, which means that with some configs and tweaks you can make a classic server.
Countless custom features which can be enabled or disabled, featuring:
Events system. It's pretty cool and modular, you can add games in them, set variable and random rewards as if they were monster drops, rewards take the players' performance into account...
Auctions system, in which rare items can appear periodically and then players can place bids with any currency.
Farm zones manager. If you're a lazy admin like me, you can specify general drops for entire zones, or even give their monsters stat modifiers.
Custom sell. Players can set stores exchanging items they have for others, not necessarily adena. Pretty handy for custom currencies or gear trades. When other players click on them they will see it like a NPC multisell.
Appearance preview. Players can navigate through all the available appearances and try them on their chars, so that they can have a better idea of which to buy. Appearance previews are only available at town and they go away after 1 minute.
Pretty damn balanced, retail-like and customizable formulas, able to balance even a server with unnerfed Dragonclaw Weapons.
Check here for another insight to the server features.
I'm still missing tons of information... there are 8 years of work behind that, and I'm too lazy atm to describe it all, so just go and play L2Tenkai to have a better idea or just run your own instance of the project and test it.
Enjoy!