I found out that pagetools can be extended by implementing the before-hook
https://www.dokuwiki.org/devel:event:template_pagetools_display in an action-plugin.
In the hook i had to check for
$event->data['view'] == 'main'
and add my entry to the
$event->data['items']
array. The entry have a key as name and a value containing the link, coded as a unordered list item:
<li><a href=....><span>Title</span></a></li>
I also managed to create a plugin doing so. At least my action works but i have some issues:
1.) how to add a custom icon for it? (i use the default dokuwiki template)
2.) is there a environment variable already containing the H1 of the page, or do i have to read it out?
3.) the icon won't fit into other templates style. Do i need to create an icon for each possible style?