If you want to change the default settings of Bitcoin Core you have to:
- Go to %appdata%/Bitcoin
- Copy “Sample Bitcoin.conf” from https://en.bitcoin.it/wiki/Running_Bitcoin
- Search about the newer configuration options (ie. disablewallet is not listed in the wiki)
- Finally edit the file with your settings
I believe that on installing Bitcoin Core, if no bitcoin.conf exists in %appdata%/Bitcoin a new one should be created with all options available in that release and some comments about every setting (like the wiki sample file).
I dont know how to make a pull request for this idea.