The app ships with an "autocomplete.txt" file that contains all the *.ini sections and keys that can be extracted from the game's executable.
I made a small bash script for this. All that is needed to update the "autocomplete.txt" file is to run this:
$ bash ./list-ini-values.sh --path <path-to-Fallout76.exe> --comma-separated > ./Additional\ files/autocomplete.txt
You can also list all available *.ini keys in a human readable form:
$ bash ./list-ini-values.sh --path <path-to-Fallout76.exe>
If you want to run this script under Windows, you need either Cygwin, Git Bash (which is often bundled with git anyway), or WSL2. Pick one.
Credit goes it u/LinuxVersion on Reddit: