This is one of the rare (only one?) JSM loaded from a worker thread in DevTools.
We have to wait for bug 1247687 before being able to convert this JSM to ESM.

This also block removing support for loading jsm as commonjs in the devtools module loader.
Once we are able to migrate it to ESM, we can move from using require to ChromeUtils.import* method and remove a few code in the loader:
https://searchfox.org/mozilla-central/rev/a26af613a476fafe6c3eba05a81bef63dff3c9f1/devtools/shared/loader/base-loader.js#343-349
(and a few dependencies of this code)

Note that there is also this JSM which is a dependency:
https://searchfox.org/mozilla-central/source/devtools/shared/validate-breakpoint.jsm