I can’t spoil the material that falls into the categories I mentioned, but Thematic Elements is a term used by the MPAA that is given to a film that features any sort of mature subject matter that may seem inappropriate for younger audiences such as defiance, coming-of-age issues, and brief shots of violence. There’s more that goes into it, but those are just some examples.
The film does feature moments of violence, but nothing too extreme in terms of content. However, do note that the film DOES feature sequences that may be scary for younger children as this is meant to be a relatively darker take on the Friendship is Magic universe.