[Kingly_Krab]

Here's the code for the regen in the source. Rest Regen occurs when they're out of combat for XX seconds, the Regen Percent occurs when they sit down. This is in client_process.cpp.

void Client::CalcRestState() {

        // This method calculates rest state HP and mana regeneration.
        // The client must have been out of combat for RuleI(Character, RestRegenTimeToActivate) seconds,
        // must be sitting down, and must not have any detrimental spells affecting them.
        //
        if(!RuleI(Character, RestRegenPercent))
                return;

        RestRegenHP = RestRegenMana = RestRegenEndurance = 0;

        if(AggroCount || !IsSitting())
                return;

        if(!rest_timer.Check(false))
                return;

        uint32 buff_count = GetMaxTotalSlots();
        for (unsigned int j = 0; j < buff_count; j++) {
                if(buffs[j].spellid != SPELL_UNKNOWN) {
                        if(IsDetrimentalSpell(buffs[j].spellid) && (buffs[j].ticsremaining > 0))
                                if(!DetrimentalSpellAllowsRest(buffs[j].spellid))
                                        return;
                }
        }

        RestRegenHP = (GetMaxHP() * RuleI(Character, RestRegenPercent) / 100);

        RestRegenMana = (GetMaxMana() * RuleI(Character, RestRegenPercent) / 100);

        if(RuleB(Character, RestRegenEndurance))
                RestRegenEndurance = (GetMaxEndurance() * RuleI(Character, RestRegenPercent) / 100);
}