Localizable.strings localized only for a single language generated incorrectly

[ralfebert]

If there is a file like Localizable.strings localized only for a single language (one folder en.lproj):

xcodegen doesn't pick this up correctly. After generating the xcode project, the file is not localized and thus not picked up at runtime:

If I add a second language just as a placeholder, it is picked up correctly:

[qunwang6]

Same question