Copy PlainText is a tiny extension that removes the formatting from the selection before copying/pasting to/from the Clipboard. Note: None of my extensions contain any tracking, advertising or privacy infringement. Features

Remove the formatting from the selection before saving to the Clipboard (Firefox restricts some functions on some URLs.)
Custom Find & Replace (string & Regular Expression) (v1.13)
Remove the spaces from the start and end of the selection
Remove multiple spaces
Keyboard Shortcuts
Paste PlainText
Help Guide

Apple/Mac Users: if the shortcut keys do not work, try System Preferences - Keyboard - then check “Use all F1,F2, etc. keys as standard function keys." Note: WebExtension API does not allow setting Copy PlainText as the default copy function of the browser at the moment. Permissions

Get data from the clipboard: Used to Paste Clipboard text
Input data to the clipboard: Used to Copy to Clipboard
Display notifications to you: Used to inform users

Optional Permissions

Download files and read and modify the browser's download history: Used only to export Preferences
Access your data for all websites (v1.14): Added <all_urls> as a workaround for Firefox bug 1841483 (1838753/1653408), to be able to inject a code into iframes to get the selected text