EDIT: sorry for duplicate info in these posts; I sort of did them for different people, and so repeated myself a bit. I don't have time to do proper write ups right now.
Database Records (the dbr files)
They're all plain-text, and so can be opening and altered outside of the art manager. However, note that the art manager will discard any information in the record that does not accord to the template.
A template is basically the underlying form for a given record type. It simply tells the Art Manager how to display the information in the record in a nice organized way by defining what the fields are, what kind of values they take, etc.. You can open a template and add a field, call it whatever you want, and then when you open the record in the art manager and set the new template, you'll see your field in the record. If you put in a value and save the record, the art manager will save that data as well (and delete any fields in the record that are not defined in the template). But, adding fields to a record this way is effectively the same thing as just opening up the record with notepad and typing in the data manually.
Skills and Masteries
The first 8 masteries (the folder with all the skills and ****) is located in Records\Skills\
The 9th mastery (dream) is located in Records\XPack\skills\
The skill tree is a record located in the same folder as all of a mastery's skills, and it lists which of the skills are included in the mastery. They are named by mastery, so earth is "earthskilltree.dbr," nature is "natureskilltree.dbr," etc.. Skills must be linked in the skilltree for the player to have the skills.
This refers to the section of the player record "Skill Trees" where each collect of skills is listed on the player so the player can start with the skills. These can be defined in records\xpack\creatures\PC\femalepc01 and malepc01 (just open up the player record and go to the "skill trees" sheet near the bottom.
In general, the xpack folder contains all the records added by the expansion.
Now, each skill has a second file that points to it for the UI, and these are located in Records\InGameUI\player skills\ (I call these uipointers). Each one is named like "Skill01," "Skill02," etc..
The uipointers are listed and defined in each mastery's panectrl record, and these are located in records\xpack\UI\skills\mastery X (where x is the number of the mastery) -- Please note that the panectrl files for the original 8 masteries is in both locations (records\ingameui and records\xpack\ui) -- the ones in the xpack override the original ones, though the panectrl files do point to the skill records in the InGameUI folder.
This record lists all the PaneCTRL records so the mastery can be selected from the main screen. This file is located here: records\xpack\ui\skills\skillswindow.dbr
Now, here is what stops a 10th mastery from entering the game:
Open skillswindow and go to the "config" sheet. In there you'll see a series of fields named skillCtrlPane1, 2, 3, etc.. And each one likns the PaneCtrl.dbr record which defines all the skills of a mastery.
As you can see, there are only 9 fields. Adding a 10th field called skillCtrlPane10 to the template does not work (the game basically stops looking after 9--or maybe the field would be called something like skillCtrlPane010, if it was already defined).
2) FemalePC01 MalePC01
records\xpack\creatures\PC\femalepc01 and malepc01
If you go to their skill tree listing, you'll see that all 10 slots are taken--9 for the masteries, and 1 for the quest rewards (most stat-related quest rewards are simply passive skills that grant the boost). Adding a skilltree10 or whatever doesn't work (nor could it without a panectrl linked in SkillsWindow). If we could have a 10th mastery defined in the skillswindow.dbr, we would be able to link it to the character and make it selectable by deleting the questrewardskilltree from the player record and replacing it with our new mastery. So, if we could at least get the game to register a 10th entry in the skillswindow.dbr, at worst we could add a 10th mastery by dumping the questrewardskill tree and moving the quest reward skills into the open slots in the existing mastery trees.
(About the other fields: QuestTree links to a skill tree with quest-only skills that are used by the game to advance quests and do things like fire the ballista at the wall, or give you an NPC follower. PotionTree and PotionTree2 are for potions and scrolls (one-shot items), and are skills you can't use without the prerequisite item.)
Now, some miscellaneous info: the buttons and stuff on the selection screen can be found in xpack\ui\skills\select mastery\masterypane.dbr. In the "config" sheet there's a field called "masteryMasteryButtons." If you double-click on the first entry it'll open an array of values (each one a mastery button).
Heh, any questions?