Translation of button hover text in Ckeditor 5

When I enable this module and add the "Iframe Embed" button to Ckeditor 5 for a specific text format, the button appears in Ckeditor 5, and this text appears on hover: "Iframe Embed". However, I am unable to translate this text into another language: this string simply does not appear in the translation interface.

I had a brief look at the code. The string exists at several places, including in editor.t("Iframe Embed") in iframeEmbedUI.js. Is it a bug on my side, or does something need to be done in order to force this string to be translatable?