Mysteriously, the <main> tag disappears

[xplosionmind]

Describe the bug
In a page, mysteriously this plugin makes the <main> tag disappear.

To Reproduce
Steps to reproduce the behaviour:

1. Clone this repository
2. Run npm i && npm run start
3. See the page https://localhost:8080/zibaldone/, and compare it against its source, in content/zibaldone-it.liquid (content/zibaldone.liquid is almost the same, but here the bug does not appear)
4. Notice how the <main> tag in that page disappears only when the plugin is enabled (these lines in the config)

Expected behaviour
The <main> tag should not be removed.

Screenshots

Screenshot of the page with the plugin activated:

Screenshot of the page with the plugin deactivated:

Desktop:

• OS: Fedora 40
• Browser Firefox
• Version 128