I now wish to add features for AB. I can't seem to figure out how to know which battleground the player is in. My WSG only addon uses "PLAYER_ENTERING_BATTLEGROUND" To decide if it should show the frame or not.
I would like to find out which battleground the player is in to have the addon show a different frame for each battleground.
Correct, but you will want to use the instanceID return (eighth value) because the numbers won't change, but there could be conflicts with the name across locales. The name is useful only to show to users while instanceID is what to use when checking the instance.
In other words, instanceID is unique but you cannot guarantee name is unique. Think of it this way: whenever Blizzard decides to provide a legacy version of a battleground, it will share the same name as the current version of the battleground (name == name) but they will have different instanceIDs to tell them apart.