what is happening, and what does the output of the terminal mean?,what is happening in the "biases' variable?

I don't understand what can help me explain 'biases', can anyone help me?

what does this output in the terminal mean?

and why is there so much data if my list has only 3 elements?

I'm new to programming, sorry

import random
import numpy as np

sizes=[5,12,18]
biases = [np.random.randn(y, 1) for y in sizes[1:]]

print(biases)

Output:

[array([[-0.34096409],
       [ 0.71416149],
       [ 0.46116949],
       [-0.0085154 ],
       [-1.14376602],
       [ 1.31237993],
       [ 1.05157063],
       [ 0.01336067],
       [-0.62518396],
       [-0.36973332],
       [-2.15854055],
       [ 0.65925235]]), array([[-0.79280421],
       [ 0.45561691],
       [ 1.33646115],
       [-0.0326803 ],
       [ 0.770597  ],
       [-0.49923431],
       [ 1.30580436],
       [-0.89544573],
       [ 1.23266028],
       [-0.06647325],
       [ 1.30798641],
       [ 0.06567199],
       [-0.07953561],
       [ 0.58575021],
       [-0.85417039],
       [ 0.68328533],
       [-1.88466084],
       [-0.88627766]])]

Process finished with exit code 0