MathType Web Integrations → Documentation → Development guide → Packaging
Each editor plugin that is distributed built (e.g. those that include a webpack.config.js file) must have a prepack npm lifecycle script, which is run BEFORE a tarball is packed (on yarn pack, yarn publish, and when installing git dependencies).
This script should build the package (generally by calling yarn run build).
As a special case, the TinyMCE plugins call the services/compile.js script because they need to have the source replaced before building.