'http://download.opensuse.org/repositories/home:/strycore/xUbuntu_16.04 ./ Release' is not signed [duplicate]
This worked for me:
wget -nv https://download.opensuse.org/repositories/home:selmf/xUbuntu_16.04/Release.key -O Release.key
sudo apt-key add - < Release.key
sudo apt-get update
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