It seems the wording on the tool tip changed with one of the patches, but I'm not sure. Maybe from skill line XP to character XP.

Khairiah wrote: »

The training trait increases the XP gained for everything.. weapon, skills, character and CPs. So they made it even faster to lvl it all.

Kinda. Training only increases XP gained from kills. It doesn't affect XP gain from non-combat activities like picking locks or turning in quests (though, it honestly wouldn't surprise me if training is bugged and increasing XP gain from things it's not supposed to). It does increase the rate all your relevant skill lines advance.

Before Dark Brotherhood, Training only increased that skill line. So a training 2h would only increase your 2h gain. A training medium armor piece would only increase your XP gain for medium armor But, that's no longer the case.

training does not affect fighters guild, fighters guild is the number of undead/deadra killed.

Darlon wrote: »

starkerealm wrote: »

Incidentally, I don't think training affects fighter's guild line advancement. But if someone wants to stack training high enough, I could be proven wrong.

Of course it doesn't, since fighters guild progress is not based on xp gained. (Just like mages guild)

It is, technically, kill XP, however. Hence the weirdness. The same is true of Werewolf, by the way. That's also a fixed kill XP progression (though, unlike FG, it actually advances on overleveled kills). Mages Guild never awards kill XP.