Merge pull request #2156 from lyz-code/master

Remove Polar Bookself

README.md

@@ -652,7 +652,6 @@ _Personal e-book management software._
   - [The Epube](https://tt-rss.org/the-epube) - Self-hosted web EPUB reader using EPUB.js, Bootstrap, and Calibre. ([Source Code](https://git.tt-rss.org/fox/the-epube)) `GPL-3.0` `PHP`
 - [Komga](https://komga.org) - Media server for comics/mangas/BDs with API and OPDS support, a modern web interface for exploring your libraries, as well as a web reader. ([Source Code](https://github.com/gotson/komga)) `MIT` `Java/Docker`
 - [Mango](https://github.com/hkalexling/Mango) - Manga server and web reader with a built-in MangaDex downloader. `MIT` `Crystal`
-- [Polar Bookshelf](https://getpolarized.io/) - Polar is a personal knowledge repository for PDF and web content supporting incremental reading and document annotation. ([Source Code](https://github.com/burtonator/polar-bookshelf)) `GPL-3.0` `Javascript`
 
 _Enterprise-class library management software._