New Features in Ver 3.0
・Features
・Additional search engines by a user
Users can add a search engine in a options page. Also you can choose the site as a default a search engine. YouTube, Amazon, MDN, ... so many sites can be used.
・Others
・For Developers
Remove unused values in messages.json.
Unify a format of br tags.
https://github.com/Soushi-Atsumi/Search-in-Sidebar
https://addons.mozilla.org/en-US/firefox/addon/search-in-sidebar/