Explanation of localization settings by environment.
These are global settings of the app found in the app builder under Environment settings > Localization.
Timezone: the default timezone of the app. This will be used if there isn’t a user associated to the current execution context (for example an event arrives from a global endpoint, where no user triggers that event). It is also used for defaults for timezone of time listeners, however it can be changed.Language: the default language for the app. Take into account that if the app is not correctly internationalized you will see a mix of languages.
Keep in mind that users can configure their localization settings in their profile and those will override the app localization settings.