Hello everyone, thanks for the fast responses.
You can find the absolute path to the program by running something like $ which your_fire_program
This gave me /usr/bin/fire
And this finally gave me the mesa-demos package, which I maybe installed accidentally...then you can determine which package owns it. $ pacman -Qo `which your_file_program`
So I could solve my problem. Thanks a lot. Best, Heiko