Yes, you can certainly open your keycommands_en.json file (the “en” part may use a different two-letter language code if you are using a non-English keyboard) in a text editor and look for the MIDI note entries. The JSON file is found in your user-level application data folder (on macOS, /Users/your-username/Library/Application Support/Steinberg/Dorico 3.5; on Windows, %APPDATA%\Steinberg\Dorico 3.5). MIDI entries are prefaced with MIDI: so they should be easy to find.