Yo! The mod is basically under indefinite hiatus since I've not had the time or motivation to continue development on it, though I do still keep an eye on comments and such in case things need to be fixed.

So the Battery Saber is a weapon that is craftable in the vanilla anvil. In order to learn the blueprint you first need to create a Steel Saber (also in the vanilla anvil), the recipe of which is already included upon creation of an Everis character. Alternatively you may also use admin commands to spawn in the desired blueprint by typing '/spawnitem itemname-recipe' - where "itemname" is replaced by the ID of the item in question.

So in short, it's obtainable in a normal playthrough, though you may also spawn it in if you feel like. The Legacy Box is specifically for items that are otherwise unobtainable/uncraftable without the help of admin commands. Hope that helps!

(edited for spelling)

Aaahhhh. That does help. Thank you. I was searching under the replicators and couldn’t find it. I probably shot way past them for the progression of the story.
Thanks again.