ModExtraAssets is no longer getting updated for classic. However, since 2024 there's a MEA Revamped version that fits BepInEx moddding BB+ perfectly!
1. Click on Classic text in About page to get the code
2. Open Assemby-CSharp.dll in DnSpy
3. Right-click on { } - and choose "Add Class (C#)"
4. Paste the code from the About page and save
5. Save the module