While integrating this plugin into the theme selector, I noticed that the last li in the list that is rendered by the changelog plugin always gets a nested h1 child element with the id "-3".
This is my markdown for the changelog:
# V 1.0.0 Alpha 2
_Second public release_
- Test
---
# V 1.0.0 Alpha 1
_First public release_
- Test
This compiles fine when viewed as a normal page:

But when viewed in the rendered Changelog entry, it looks like this:

Note the black bar in the last entry. This issue arose most notably as I tried to adjust the css to accommodate dark mode by integrating with their vars. This can also be verified by inspecting the element:

I guess this is a bug, because with the id -3, it appears to be not specifically selectable. The following selectors did not allow me to hide the last h1:
#-3 { visibility: hidden !important; }
h1#-3 { visibility: hidden !important; }
#CHANGELOG_RENDERER h1#-3 { visibility: hidden !important; }
#CHANGELOG li > h1#-3 { visibility: hidden !important; }
#CHANGELOG li > h1 { visibility: hidden !important; }