Following the accepted answer to this question, I have adjusted the ppa entry for geogebra to the following entry:
deb [signed-by=/usr/share/keyrings/geogebra.gpg] http://www.geogebra.net/linux/ stable main
This works very well, however occasionally the file /etc/apt/sources.list.d/geogebra.list seems to get overwritten and reverted to the old version:
deb http://www.geogebra.net/linux/ stable main
When is this file overwritten? How can I prevent this, without reducing the security level (meaning: I want the particular key to be usable only for the particular ppa and software)?
I am on (K)Ubuntu 23.10.