Compiler 4.1.7 with flags: -l 3 -O 2z gives the following warning:
WARNING: monkey.jungle:213: fenix3 does not support language 'heb'
While it is technically correct it is confusing because there's a legitimate use case to have Hebrew language translations for fenix3: even though the device doesn't support Hebrew it's still possible to use the Connect IQ app on a device with Hebrew as system language and thus see the settings with the Hebrew labels.
Of course the best would be if you could add this feature: https://forums.garmin.com/developer/connect-iq/i/bug-reports/feature-request-split-the-strings-xml-for-in-device-and-settings-related-strings and then the compiler could display the warning when we try to add translations for the device but would not give a warning when we only add translations for settings or even for displaying the fit file with Hebrew translation.