Set random seed for matplotlib plotting backend

I am generating saving SVG images using matplotlib and would like to make them as reproducible as possible. However, even after setting np.random.seed and random.seed, the various id and xlink:href values in the SVG images change between runs of my code.

I assume these differences are due to the backend that matplotlib uses to render SVG images. Is there any way to set the seed for this backend such that identical plots produce identical output between two different runs of the code?

Sample code (run this twice, changing the name in plt.savefig for the second run):

import random
import numpy as np
import matplotlib.pyplot as plt

random.seed(42)
np.random.seed(42)

x, y = np.random.randn(4096), np.random.randn(4096)
heatmap, xedges, yedges = np.histogram2d(x, y, bins=(64,64))

fig, axis = plt.subplots()
plt.savefig("random_1.svg")

Compare files:

diff random_1.svg random_2.svg | head
35c35
< " id="md3b71b67b7" style="stroke:#000000;stroke-width:0.8;"/>
---
> " id="m7ee1b067d8" style="stroke:#000000;stroke-width:0.8;"/>
38c38
<        <use style="stroke:#000000;stroke-width:0.8;" x="57.6" xlink:href="#md3b71b67b7" y="307.584"/>
---
>        <use style="stroke:#000000;stroke-width:0.8;" x="57.6" xlink:href="#m7ee1b067d8" y="307.584"/>
82c82
<        <use style="stroke:#000000;stroke-width:0.8;" x="129.024" xlink:href="#md3b71b67b7" y="307.584"/>