: Do not dump files directly into the archive. Place everything inside one main folder so it doesn't clutter the user's directory upon extraction.
Knowing if it's for a specific software, hardware (like a Chromebook N21), or a coding project would help me give you a much more precise description of what it should contain.
In many developer and engineering communities, filenames like k.n21 are used as shorthand for specific versions or hardware revisions.
Regardless of the specific data, a "proper" 7z archive should always follow these best practices:
: It should contain the modified assets, a manifest file, and an installation guide. 3. Standards for "Proper" 7z Contents