Let me explain again. Let’s take an example you are using English for US language on your site, and the language files are en_US.po and en_US.mo, Now rename those files as woodmart-en_US.po and woodmart-en_US.mo and place those language files under wp-content/languages/themes It will not be overridden again when ever you will update the Theme same as for other languages you are using.
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