Setting a Default Reference Language is useful when working with localization files that contain string IDs/keys. It can be set by the project owner and administrators, on a project level, for all contributors to see in the translation pages.
How to set a Default Reference Language
1) Add your software's source language to your POEditor localization project using the Add Language button in the project page.
2) Click on Import in the project page to bring the terms (the string IDs) from the localization file to the localization project and the strings in your source language in the language added at step 1.
If this is your first import, the language where you uploaded the translations should be automatically set as DRL.
To change the DRL, go to Settings > General, click on Edit, select your desired Default Reference Language and click on Save project details.
Contributors can choose any other language in the project as Reference Language, just for themselves, if they are granted Contributors Can Set Reference Language in the project's settings, by the project owner or by an admin.