As seen in this example: https://api.guildwars2.com/v2/skills?ids=13009
When a skill has split facts the API simply returns multiple objects with otherwise identical labeling. I might assume by convention that the first copy of the fact is for PvE, but this is not explicit in the actual response, nor is there an indication that it is split at all, this has to either be assumed or referenced by checking in game. Now that the balance team has more leeway to make changes specific to PvP and/or WvW some more clarity will be needed. As necessary, please either modify labeling of the response data to indicate mode variations when different from PvE, or refactor the response to produce separate fact arrays for each mode.