Regarding the name: along what we are discussing about the machine translation extension, the current name application-glossary-machine-translation could be a good fit (to be understood as “glossary for machine translation”). Another more accurate name would be machine-translation-glossary since it is the dedicated term used in this field as far as I can see:
However with the app parent prefix it would become application-glossary-machine-translation-glossary which sounds a bit heavy. Unless using machine-translation-glossary within the Glossary app can be considered but I doubt it. No real preference between keeping it in the same repository or creating a new one. Note that in the future we could consider creating a distinct app machine-translation-glossary which would manage machine translation glossaries in a generic way, not necessarily bound to the way the Glossary app implements glossaries.
Taking into account these considerations, Vincent, would you be fine with the current name? What do you think?