I would like to create a plugin to introduce a new contenteditable section that can be edited without the intervention of CKEditor, so without altering the source code. But I do not know what hooks to use. I have something on:

http://www.typesettercms.com/Plugin_Hooks

but the documentation seems incomplete. Where could I find out more?

If I find a starting point, I will develop the plugin on GitHub and probably many people would be interested.

What do you think ?

Extra sections are defined with   <?php gpOutput::Get('Extra','Another Area'); ?>   in the template put anywhere) and then edited in the CMS under  content -> Extra content  : Another Area

For the definition and application of hooks You can klick at the hook or (with a tool like Super Finder XT) go through the source of the Typesetter - master (5.1b1 and 4.61)  and of  some plugins who use the hooks.

Perhaps https://github.com/juek/CustomSections can help You further ?  

You can also try native javascript like  https://developer.mozilla.org/en-US/docs/Web/API/Node/insertBefore (and https://stackoverflow.com/questions/4793604/how-to-insert-an-element-after-another-element-in-javascript-without-using-a-lib)

Thanks a lot for the response and for the information provided. I use the SynWrite editor and am pleased with it. I saw that Juek's plugin, CustomSection, is very useful.
I tried to create a plugin, which I uploaded to GitHub. I hope it is useful to someone and can be further developed.
Here is the link.

Also interesting are the links from mozilla and stackoverflow, I will study them carefully the next few days.

Thank you again!

Hm - Your addon is quite useful, but i  like ckeditor , which has an inbuild security token, and the modified codesnippet plugin, which You can find in typesetter under plugins -> available -> Syntax Highlighter. A much simpler editor is cleditor.

It just adds a <pre> at the moment and needs a modification. (div instead pre)

There ist also Code Editor,  Code snippet Geshi and  Paste Code.  You can evtl.  overtake some functions into Your plugin.

* What we do not Yet have, is a direct Cms- editor for the template and connected js-css- files , which can be implemented by Elfinder and its mods for subdirectories together with codemirror, which is already used in the layoutmanager (also as a replacement for gpfinder possible)