These are special effects created for pages on Hot Page. Read more at https://fx.hot.page/.
To modify the files and see the results, you can run a development server.
npm start
If you get the error Error: ENOENT: no such file or directory, open './localhost-key.pem' that is because you haven't created an SSL certificate yet (see below).
Once you can start the server, the files in src/ will be available at localhost like https://localhost:8000/drop-reveal.js. Be sure to use https or the browser will show you a cryptic error.
To run the server and use this with your pages on Hot Page, you will need to serve these files using encrypted https. To do that, it is easiest to install a valid SSL certificate for localhost. This keeps the browser from freaking out when it loads the files. You can install a certicate easily using mkcert (you can read more on web.dev). For example, on MacOS use the following
brew install mkcert
mkcert -install
mkcert localhost
This will generate the certificate in this directory and you should be able to run the server.