Found by Ophelia. Anet: I am excited to reveal that on August 8th we will be adding Gliding to WvW. The team has been working hard on a way to make gliding in WvW feel fun and fair, and by using our brand new territory system, we believe we finally have come up with a way to accomplish both goals.
Gliding in WvW does not require unlocking gliding through PvE masteries. Instead, you can acquire Gliding by using ability points in the new Heart of Thorns War Gliding Mastery. The War Gliding Mastery is available to those who own Heart of Thorns and allows gliding in territories that your team owns in the Mist War maps. We have also replaced Ballista’s fourth skill with an anti-air bolt skill that shoots people out of the air and immobilizes them for a short duration. With the August 8th update, we are also adding a new ability point reset vendor, the World Ability Master, to every portal/home keep (team starting area).Read More: https://forum-en.guildwars2.com/forum/game/wuv/Gliding-and-Territories-in-WvW