I have previous posted that I only ever use one ‘unofficial addon’ being the tvthemes addon. I can fully understand why this addon is not official due to it playing copyrighted theme tunes. However, I do not use it for that purpose, I use it to play video trailers as fanart. I am not sure of the legalities of this and in the eyes of the law, I guess this might be one and the as theme tunes as far as copyright goes.
Anyway, if someone with more knowledge on the topic could confirm if the playing of trailers is a breach of copyright or not, could the ability to play trailers as fanart be added to kodi, preventing the need to use an unofficial addon ?