TF2 attributes related to "item_meter"

item_meter_attributes.txt

item_meter_charge_type: 2-bit bitmask
  bit 0 [0x1]
    - if set: CTFPlayerShared::UpdateItemChargeMeters will passively recharge
      - only if item has IHasGenericMeter as a base class
      - only when item->ShouldUpdateMeter() returns true
      - rate is based on: item_meter_charge_rate * mult_item_meter_charge_rate
      - rate is also affected by item->GetMeterMultiplier()
  bit 1 [0x2]
    - if set: CTFPlayer::OnDealtDamage will recharge when dealing damage
      - but not if: playing MvM mode and playing as pyro and weapon is in secondary slot
                    and weapon is Gas Passer and dmg custom is TF_DMG_CUSTOM_BURNING
      - only if item has IHasGenericMeter as a base class
      - only when item->ShouldUpdateMeter() returns true
      - amount charged is affected by dmginfo.m_flDamage and mult_item_meter_charge_rate

item_meter_charge_rate:
- determines the base passive charge rate (when item_meter_charge_type bit 0 is set)

item_meter_resupply_denied:
- if  > 0: CTFPlayerShared::Spawn won't call SetItemChargeMeter(GetDefaultItemChargeMeterValue())
- if != 0: CTFPlayer::Regenerate won't call SetItemChargeMeter(GetDefaultItemChargeMeterValue())

item_meter_damage_for_full_charge:
- sets the scale for damage-based charge gains (when item_meter_charge_type bit 1 is set)

mult_item_meter_charge_rate:
- scales passive charge meter gains (when item_meter_charge_type bit 0 is set)
- scales damage-based charge meter gains (when item_meter_charge_type bit 1 is set)


Note that there is no attribute to determine the starting value of the item meter.
That is controlled entirely by the game code (via virtual func CBaseEntity::GetDefaultItemChargeMeterValue).
The base function returns 100.0 (i.e. almost all generic-item-meter items will spawn with 100% charge).
The only class which overrides it is CTFJarGas (Gas Passer): it returns 0.0 (i.e. spawns with 0% charge).

The default spawn charge can be modded fairly easily; but it cannot be affected merely via item attributes.