The extract translations from the source code to be sent to Transifex for translations isn't including the plugins source code folder.
From my calculations, 145 strings aren't being sent to Transifex for translate because of this problem.

The extract translation uses the frontend-build:

The frontend-build only includes the src folder to extract translations:
https://github.com/openedx/frontend-build/blob/c70ef4e0a5e8702f7144f36b1b23195b94f5e09a/bin/fedx-scripts.js#L73-L76

IMO: If the plugins folder is only specific to this repository, this fix should be made on this repo, if the plugins usage is a patter that is going to be replicated to other repositories, then the extract could be fixed on the openedx/frontend-build repo.