Sorry, but I don't understand what you mean with the developer database.

If you are afraid of installing the plugin in "regular" Joplin, other users have reported that it works fine on their machine. The code shouldn't touch your notes unless you right-click and change a word, and then it will only change that word. I can't promise it won't do anything to your notes (because it is software) but I have programmed it to not interfere with the database directly and only changes the notes when the user instructs.

The only problem I have is that on my machine it does not work when installed from the repo and I have to install it directly from source.