Converse has a special build called the headless build.
You can generate it yourself by running make src/headless/dist/converse-headless.js
in the root of the converse.js repo.
The headless build is a bundle of all the non-UI parts of Converse, and its aim is to provide you with an XMPP library (and application) on which you can build your own UI.
It's also installable with NPM/Yarn as @converse/headless.
The main distribution of Converse relies on the headless build.
The file src/headless/index.js is used to determine which plugins are included in the build.