Mostly just by word of mouth. Basic problem is a lot of stuff is being confirmed but you need to be at the event to have the evidence.
Emma Bessho’s Voice Actress, Yuna Kamakura, at the Duel Opera, scripted Duels done at Jump Festa, was scene/overhead using two of Emma/Ghost Girl’s Altergeist cards from her Duel against Blood Shepard:
Altergeist Dragvirion, a Synchro Monster for Altergeists
Altergeist Haunted Rock, a Continuous Trap Card for Altergeists
When there is more information, we’ll mention it.