1.)
https://xdsoft.net/jodit/ (webseite)
https://github.com/xdan/jodit (github)

sudo apt update
sudo apt install nodejs npm

mkdir jodit-build && cd jodit-build
npm install jodit

2.)
https://github.com/ajaxorg/ace-builds
https://github.com/ajaxorg/ace-builds/tree/master/src-min-noconflict
https://github.com/ajaxorg/ace-builds/blob/master/src-min-noconflict/ace.js

3.)
https://github.com/beautifier/js-beautify

4.)
http://htmlpurifier.org/download

5.)
https://github.com/PHPMailer/PHPMailer/

Update_Test_PHPMailer.php