Installation in Empathy:
We extract the downloaded file in the folder ~ / .local / share / adium / message-styles /. We choose the theme in the preferences of Empathy.
Installation in Emesene:
As root, we extract the file in / usr / share / emesene / emesene / themes / conversations, and then we select the topic Adium Ambiance in the preferences of Emesene.
I asked the author if there will be a theme for Pidgin and he replied that very soon, so I look forward to it.