I’ve noticed that the percent values such as zoom are not formatted according to the locale.

For instance, for Turkish, percentage sign is prepended to the number (%100). In most European languages, there is a non-breaking space after the number (100 %). However, in the app a standard format seems to be used. Some other languages use a completely different sign (Arabic, CJK languages etc.).

To remedy this, locale-aware percent formatting can be used. Intl has an option for this, it is very handy.