How does pontoon determine the default locale?

I’m trying to sync a project that has two directories: en-US (default) and zh-CN, but when I sync, Pontoon is selecting the wrong one as the default.

Why would this happen?

Is there a simple way to correct the issue, for example a way to manually set which locale is the default?

It is additionally strange because the wrong file is being chosen as default only in the instance I deployed on heroku (, but locally, the proper one is being synced - what could be the difference?

Pontoon looks for directories named “templates”, “en-US” and “en” to find source strings in.

This is sadly hardcoded. See

interesting! but then what could explain the sync not pulling en-US by default, and instead using zh-CN? It worked for the first sync that I performed, but then I made some updates to the repo and tried to sync again, which caused it to flip to pulling from zh-CN. This did not happen in my local build, though :thinking:

also +100 on being able to define source locale in the project admin page :slight_smile: