I’ve never found anything online specifically talking about what weapons and other items your followers prefer or will use. Some of it is self-explanatory, some less so. Looking at the follower’s inventory, I see they have large markers and small markers next to items, just as the player does. I know that large markers in your inventory means items you’ve equipped and small markers means items you’ve favorited. You can’t favorite items in your follower’s inventory, so small markers in their inventory must mean items they like and will use under certain circumstances, but do not currently have equipped, and large markers mean items they do currently have equipped. My guess is, if items in their inventory have neither a large nor a small marker next to them, that means the follower will never equip that item under any circumstances (unless you take one of their preferred items), and they are just carrying deadweight, so you might as well sell or store it as soon as possible. Am I right? Thanks.