What is the problem?
Some translations in SVGs are not recognised by the tool. They don't appear in the "From" translation dropdown and they are not in the SVG if you download it from the tool (like it has been stripped out).
This also means that, if you upload a new translation to Commons it will override all the translations it did not recognised. So in the above example, that SVG also had a zh-hk translation, but that has been overridden when I uploaded the fr translation.
So far, all the missing translations have codes of the form "xx-xx" (e.g. zh-hk). I have not seen it happen for languages such as "en", "simple", etc. I have not tested this exhaustively.
On the other hand, the tool does recognise all the languages (including things like zh-hans) for this SVG.
Steps to reproduce problem
- Find a translatable SVG image
- Enter a translation for a language with a dash, e.g. es-419, zh-my
- Upload this file to Commons
Expected behavior: After the upload succeeds, you will see your new translation in the "From" dropdown
Observed behavior: Your new translation is not in the dropdown. The SVG you download from the tool will not have the translation.