small demo

put up a demo I was using to check out features, feel free to use any of it if you want
https://github.com/jeremy-coleman/preactive-htm

it has both rollup and webpack builds with babel and without.

I added rollup because i wanted to look over the non-minified bundled code and noticed that the babel plugin wasn't working, I assume because of .mjs extension - might be worth noting in the readme or something. probably a lot of pepople dont know if you use resolve.extensions in your webpack config it resets all the defaults (to exclude mjs) it's also required to manually add to rollup inside the babel plugin.
if u want to see the difference just change the rollup config from: babel({extensions: [".ts", ".tsx", ".js", ".jsx", ".mjs"]}), to: babel(). Gonna explore a bit more with a real app

Review the linked preactive-htm demo, especially its Rollup and Webpack configurations, and compare the Babel plugin behavior with and without the listed .mjs extension. Check the project README for existing build guidance; the issue is complete only when the intended .mjs handling and any needed documentation are clearly established.

Written by the indexing model from the issue text.