Reproduce: I enabled Arabic as default language for Firefox in MacOS. Issue: Now, I have a mixture or Digits format between Arabic Numbers & Hindu-Arabic Numbers. As you can see even with Firefox version from About window: 81.0.2 ‏(٦٤ بتة) and Developer Tools too, see attached screenshot. Note for Translators, Arab Countries don't use same digits formats. - Eastern Arab countries are using Hindu-Arabic Numbers (٠١٢٣٤٥٦٧٨٩) - Western Arab countries are using the Arabic Numbers (0123456789 which are universal in this era) References: - https://en.wikipedia.org/wiki/Arabic_numerals - https://en.wikipedia.org/wiki/Eastern_Arabic_numerals Workaround: I switch back to English when needed. And usually keep another browser for development. How It should be: I am from Algeria (a Western Arabic country) & an developer (hobby). I expect to set Arabic language with Arabic Numbers format (and It is already set in MacOS preferences) Possible Correction: - Split Arabic Language locale into 2 (East & West) or Have a special settings for locale formats - I thing most programmer are using dev tool in English even Firefox in mother language. Not sure how to fix this. It is similar to CLI that are not translated to cursive and RTL scripts.