I am not a JS/Node/npm guy, so I hope I am not just missing something; but I would not expect that a version meant for distribution would contain what seems like autogenerated code coverage testing code.
It can be found in all of the following files:
discord-irc/dist/logger.js
discord-irc/dist/errors.js
discord-irc/dist/helpers.js
discord-irc/dist/bot.js
discord-irc/dist/validators.js
discord-irc/dist/index.js
discord-irc/dist/cli.js
discord-irc/dist/formatting.js
discord-irc was installed using the npm install discord-irc command (node.js12.16.1, npm 6.14.2).
EDIT: Removed a symlink from the list of files.