Those bonuses only apply to level 40 characters that are built with 1 (single) or 2 (dual) classes.
All classes that can cast spells:
- Single: +3 DC to all spells
 - Dual: +1 DC to all spells
 
Barbarian:
- Single: +1 damage reduction, +2 (simulated) strength when raging
 - Dual: +1 damage reduction
 
Bard:
- Single: +1 to all skills, AC, damage and saves to bard song and curse song
 - Dual: +1 to skill to bard song and curse song
 
Cleric:
- Single: can heal/harm up to 60% of the damaged hit points (instead of 50%), up to 300 hp (instead of 250 hp)
 - Dual: can heal/harm up to 60% of the damaged hit points (insted of 50%)
 
Fighter:
- Single: +6 damage with specialized weapon/s
 - Dual: +2 damage with specialized weapon/s
 
Monk:
- Single: +1% movement speed bonus every 5 monk levels, the base unarmed damage is 2d12 when medium sized and 3d6 when small sized
 - Dual: +1 movement speed bonus every 5 monk levels
 
Paladin:
- Single: +15 dispel DC (25) to weapons with Holy Avenger
 - Dual: +5 dispel DC (15) to weapons with Holy Avenger
 
Ranger:
- Single: +3 to favored enemy bonuses
 - Dual: +1 to favored enemy bonuses
 
Rogue:
- Single: +3d6 sneak attack damage
 - Dual: +1d6 sneak attack damage
 
Arcane Archer:
- Dual: +1 to enchant arrow feat
 
Dwarven Defender:
- Dual: +2 damage reduction
 
Pale Master:
- Dual: +1 real caster level (extra spells, extra damage, duration, spell penetration, resistance vs dispel)
 
Weapon Master:
- Dual: +1 AB