Odd graphical quirk in charts

[martinthomson]

https://glam.telemetry.mozilla.org/firefox/probe/http_channel_disposition/explore?activeBuckets=%5B%2210%22%2C%229%22%2C%228%22%2C%222%22%2C%2211%22%2C%223%22%2C%221%22%2C%220%22%2C%2212%22%2C%224%22%5D&process=parent

See the little blob in the top-level corner? I thought I had something on my screen, but it turns out there is a lot of SVG there.

There are as many of these as there are lines on the chart (in this case, there are 10, each one with a color that matches the chart colors):

<g style=""><g><path d="M0,-4.719L1.06,-1.458L4.488,-1.458L1.714,0.557L2.774,3.818L0,1.803L-2.774,3.818L-1.714,0.557L-4.488,-1.458L-1.06,-1.458Z" fill="#4e79a7"></path></g> </g>
<!-- pattern repeats -->

I had to open an SVG editor, but this is a star! It seems to be cropped though, so only one of the points is making it onto the page. There are already stars on the graph though, so I wonder whether this should be there at all.