Hello kovidgoyal,
thanks for pointing me in the right direction. I got a working system back.
It seems I felt - sort of - victim of my own paranoia. (with some friendly support from the calibre installer).
Short story:
My root user has "umask 077" in the shell startup files.
Setting this to "umask 000", rerunning the installer, running "kbuildsycoca4 --noincremental", logging out and in again fixed it.
Moral of the story:
To me it looks as if the calibre installer should use explicit permission for the installed files, instead of (implicitly) relying on umask.
Here are the details:
Code:
:> kbuildsycoca4 --noincremental
...
kbuildsycoca4(12056) KBuildServiceFactory::createEntry: Invalid Service : "/usr/local/share/applications/calibre-ebook-viewer.desktop"
kbuildsycoca4(12056)/kdecore (services) KServicePrivate::init: The desktop entry file "/usr/local/share/applications/calibre-lrfviewer.desktop" has Type= "Application" but no Exec line
kbuildsycoca4(12056) KBuildServiceFactory::createEntry: Invalid Service : "/usr/local/share/applications/calibre-lrfviewer.desktop"
kbuildsycoca4(12056)/kdecore (services) KServicePrivate::init: The desktop entry file "/usr/local/share/applications/calibre-gui.desktop" has Type= "Application" but no Exec line
kbuildsycoca4(12056) KBuildServiceFactory::createEntry: Invalid Service : "/usr/local/share/applications/calibre-gui.desktop"
kbuildsycoca4(12056) parseLayoutNode: The menu spec file contains a Layout or DefaultLayout tag without the mandatory Merge tag inside. Please fix your file.
Ahhh...
Ok, looked at the file (as root) found no problem. Huh ?
Code:
godot:> desktop-file-validate /usr/local/share/applications/calibre-ebook-viewer.desktop
/usr/local/share/applications/calibre-ebook-viewer.desktop: error: while reading the file: Permission denied
Ahhhh [2]
Fixed the permissions (for all calibre files there); run kbuildsycoca4 again; logged out and in again -> Big disappointment; still not working.
Then I came up with the approach, described below "Short story".