Before some people get all worked up, the question is being asked in the context of modding.
https://en.wikipedia.org/wiki/Video_game_piracy
Video game piracy is the unauthorized copying and distributing of video game software, and is a form of copyright infringement.
Okay, so at least in one (and probably the major and common one) case it the sharing is illegal due to copyright law rules. But how exactly are game files protected and what exactly is protected?
https://en.wikipedia.org/wiki/Intellectual_property_protection_of_video_games#International_standard
This standard treats the whole game as a singular component but does not define what would be covered by such a protection and what would be excluded. WIPO had recognized the complexity inherent in copyrighting video games, saying: "Although Article 2 of the Berne Convention provides a solid basis for eligibility for protection of video games by copyright, they are in fact complex works of authorship, potentially composed of multiple copyrighted works." WIPO has also stated in one of its reports that "there is no clear classification of video games and their protection will vary depending on each particular game and the elements that are part of it. In this sense, video games can be treated as computer programs and, thus, are classified as works of authorship; in that case, the source code for a video game is classified as a literary work. If pictorial or graphic authorship predominates, a video game may be classified as a visual arts work. Similarly, if motion picture or audiovisual authorship predominates, a video game may be classified as a motion picture/audiovisual work."
I understand that things differ between countries, let us stay in International/USA space. So, according to this standard videogame medium considered a whole piece and even a small portion of that piece, even if it makes not sense outside of the whole or bears no value (copyrightable value i.e. creative and original content) is protected?
Let's take, for example, a typical videogame that is made on a generic-purpose videogame engine such as Unreal Engine 4 or Unity3D Engine. When the game is packaged as a final product it contains a lot of stuff that is fairly easy to determine as protected and copyrighted work: audio assets (music, sound effects), graphical assets (textures, sprites, etc), other visual assets (3D models aka meshes, protected design-wise) and so on. This packaged game is our videogame medium. But along with this game, a bunch of meta-data is packaged as well. This metadata has no possible copyrightable value by definition (and can be actually considered as a "fact" or "factual data") and it does not even belong to the IP holder/wonder but rather, in some way, to the creators of the tools itself (Unreal Engine, for example). Let say all this data is in one single file that is being shared - how would copyright law protect against this kind of sharing?
For the context, this is somewhat follow-up to Can digital signature/Hash sequence be copyrighted?