Any way to get UDT to ignore files when bundling a UXP Plugin?

I made the mistake of making my plugin repo the same as my git repo, which means that UDT is also secretly bundling the hidden .git folder into the plugin. Are there any .ignore file types similar to a .gitignore that will tell UDT to NOT bundle it in when you make a .ccx file?

No. I suggest you would move this responsibility to your bundler/building tool. So that output of your plugin would go into subfolder rather than project root.

Done! Thanks Jarda. In hindsight I should have structured the directory like this from the beginning.

Yes, it is good practice. Later, it will be handy when you need to ship minified code instead of all source code base.