I have a task to override most of admin panel pages with custom, however I couldn’t do that. I created the same directory structure as in strapi github repo for admin package, but nothing happened
src
├── extensions
│ ├── admin
│ │ └── admin
│ │ └── src
│ │ └── pages
│ │ └── HomePage
│ │ ├── ContentBlocks.js
│ │ ├── HomeHeader.js
│ │ ├── index.js
│ │ └── SocialLinks.js
│ └── content-manager
│ └── strapi-server.js
├── index.js
├── plugins
└── themes
└── override.cs
Update 03/08/2022
It looks like Strapi team decided to remove customization options in v4, so if you want to override something like dashboard pages you'll have to use patch-package