There is no Linux specific box, but you got the rest right. If you buy the physical release you will get a DVD and a code. Simply activate the code on your steam account and install the game on whichever computer you want, as often as you want. The game supports Linux, macOS and Windows out of the gate.Thanks for your response.
So can I for example get a box set for Linux, use the code on it to play the game on my temporary Macbook Pro and when I finally buy a new laptop (whatever OS I use), just log in, download the game again(it'll be linked to my steam account right) and play it.
Sorry about the noob questions, I am a DS/3DS gamer and don't really play on my PC because its really old.