Yes it's right, you can now help test out the latest and greatest for Fireworks Mania by switching to the 'experimental' branch.
How you switch, how you get started creating mods and more can be found in the video below.
Links to various resources can be found in the description of the video on YouTube.
DISCLAIMER: All this is only on the 'experimental' branch as of writing. This means I'm still heavily developing on it, meaning it is not done yet... but now that I think about it, when is a game actually "finished" these days? :)
You of cause need to own the game to be able to try this, luckily you can buy it right here.
https://store.steampowered.com/app/1079260/Fireworks_Mania__An_Explosive_Simulator/
- Enjoy!