Those entries are created by the community. If you want Zimbabwe to appear there you will probably have to create the localisation yourself.
To do so
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Request Zimbabwe localisation is add by posting in this thread Localizations - New way to contribute that should result in a blank entry for Zimbabwe.
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Login to the localisation for Zimbabwe to customise it for local requirements. To see what is possible create some test business an set the country to a localisation which has had significant work done on it, see https://www.manager.io/localizations/
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When your changes to the Zimbabwe localisation have been approved, they will be available to you and all other Zimbabwe users in the menu you initially referenced.