dissoc-nonguix are packages and services that have non-free licenses and/or have package definitions that use pre-built sources
Add the channel to the file: ~/.config/guix/channels.scm If the file does not exist it may need to be created.
(append %default-channels
(list
(channel
(name 'dissoc-nonguix)
(url "https://github.com/dissoc/dissoc-nonguix.git")
(branch "main")
(introduction
(make-channel-introduction
"084a499cab2a827e9127c33e9ec24f1d14180c93"
(openpgp-fingerprint
"95D3 7A96 EC54 79CE 6082 5831 81FF 5EC7 66ED 8C39"))))
...))