Under Lifting and Carrying (PHB 176) it says:
Your carrying capacity is your Strength score multiplied by 15. This is the weight (in pounds) that you can carry... You can push, drag, or lift a weight in pounds up to twice your carrying capacity (or 30 times your Strength score).
and also specifies that a tiny creature can carry half as much.
A sprite familiar summoned through a warlock's Pact of the Chain feature has a strength score of 3 and so has a carrying capacity of 22.5 pounds, and a push, drag, lift limit of 45 pounds. The sprite stat block also specifies, however, that they wear leather armor and carry a longsword and shortbow.
By the rules in the PHB, these weigh 10 pounds, 3 pounds, and 2 pounds respectively, but considering they are smaller than those worn by a medium humanoid it one should assume that they do not weigh as much.
Is there any official guidance as to how much the sprite familiar's equipment counts against its carrying capacity?