about system does not work

[leszek]

This is the old package. Like I said you need the one from our testing repo if you installed plasma 5.10 from the testing-neon repo.

Code:

apt-cache policy kcm-about-extended

shows you a list of available packages.
If you want the latest and have testing repo enabled install it with

Code:

sudo apt-get install kcm-about-extended=0+p9+git20170531.1100-0ubuntu1

(If I made a typo here please correct it and use the correct version numbering showing up in apt-cache policy)