Editing WoW:API COMBAT LOG EVENT (section)

=== Prefixes ===
{| class="darktable"
|-
! Event Prefix
! Description
|-
| SPELL_
| Spell is the prefix for most effects even if the spell is a DoT or channeled.  IE when the spell begins to be cast, SPELL_CAST_START is fired and not SPELL_PERIODIC_CAST_START.  This is the same with _MISS, _FAILED, etc.
|-
| SPELL_PERIODIC
| Spell_PERIODIC Only the effects that are periodic start with this PREFIX.  IE: Successfully casting a DoT only happens once therefor even though the spell is periodic use the SPELL_ prefix.  However, the damage is periodic so it will start with SPELL_PERIODIC_.  90% of the time you will only care about _DAMAGE or _HEAL.
|-
| SPELL_BUILDING
| SPELL_BUILDING New in WotLK, assumed to be damage that can affect destructable buildings.
|-
| ENVIRONMENTAL
| sourceGUID = "0x0000000000000000", sourceName = nil
|}