In Kate extensions menu there only few plugins. Especially there is no tab bar extension. Navigation if more than one document opened is ugly - you need to use left part for files with most of space useless.
KDE recommends much more plugins: https://docs.kde.org/stable/en/applications/kate/kate-application-plugins.html
I tryed to compile tab bar extension from kde-apps: http://kde-apps.org/content/show.php?content=89786&forumpage=0
And I’ve got error: Error: Undefined interface
I have followed instruction in thread:
apt-get install apt-file
apt-file search kate/pluginconfigpageinterface.h
And found nothing. This means there is no ppa for KDE dev? If so, how to add it manually?