Pocket Editor от k5md

Pocket Editor allows you to quickly compose your documents right in the sidebar while browsing, which is very useful when collecting some data for publications, because it breaks the tedious "copy - switch to editor - paste - switch to browser" cycle!

What's most exciting - it supports editing multiple documents at once - you have as many open documents, as you want and switch between them using buttons in the bottom. To rename document one should click on its title.

Note, that it is a regular browser extension, and that is why it has no access to local files on users PC. However, all the extension data, related to one's documents is stored in indexedDB, it won't get lost. And there is always import/export feature to save users' time.