Hi
I was looking at the code on https://b2evolution.net/downloads/ as I was checking the code for the buttons as mentioned in https://forums.b2evolution.net/download-plugin-module

There are a number of warnings and errors which you can see at

https://validator.w3.org/nu/?doc=https://b2evolution.net/downloads/

You may consider them not important enought to urgently resolve :)