The Character window

Every number the game uses about you, in one place. Open it from the Character button under your paper doll (Equipment, U).

Your accuracy, strength and defence for the style you're using, your max hit and swing speed, your walking speed, and your bonuses from gear, gems, pets, work clothes and food, with where to get more of each.
Click any stat to see how it adds up.

Your doll is on the left, with a Melee / Archery / Magic switch: another style shows what your best weapon for it, from your bag or bank, would give.
On the right are that style's numbers, your defence, your attributes and your hit chances where you stand. Combat in full, Skilling, Loot and luck, and Buffs open up beneath them.
Nothing in it is sent anywhere: it's worked out on your screen from what you're wearing.