Create a new issue on our [Issues page](https://github.com/coteditor/CotEditor/issues). You can write your feedback either in English (recommended) or in Japanese.
Search for existing issues first. If you find your issue previously reported, post your case to that issue; otherwise, create a new one by filling up the "Bug report" template. Do not hesitate to post the same phenomenon to the existing issue as long as the cases are less than 10. Multiple instances help a lot to find out the cause. In that situation, include your environment (versions of both CotEditor and macOS) in your post.
Search for existing requests first. If you find your feature previously requested, post your comment to that issue; otherwise, create a new one by filling up the "Feature request" template.
Bug fixes and improvements are welcome. If you want to add a new feature or the change is huge, it's better at first to ask the team whether your idea will be accepted.
Fixing/updating existing localizations is always welcome. The project team adds `FIXME:` tag as a comment in the localized strings files if there are updated strings to be localized.
If your localization makes the Autolayout destroy, try first making the sentence shorter. However, if it's impossible, then just tell us about it with a screenshot when you make a pull-request. We'll update the storyboard file to layout your localized terms correctly.
By localization, use macOS standard terms. It might be helpful to study native Apple applications like TextEdit.app or System Settings to know how Apple localizes terms in their apps.
We recommend to utilize [Apple Localization Terms Glossary for macOS](https://applelocalization.com/macos) by Kishikawa Katsumi to find macOS-friendly expressions. This service enables us to search in the texts localized by Apple for macOS applications and frameworks.
You also need to take care of how Apple treats punctuation characters and symbols. For example, regarding quotation marks, they normally prefer the typographer's ones.
Copy one of a whole .lproj directory and use it as a template. We recommend using `CotEditor/en-GB.lproj/` directory because they are always up-to-date.
Continuous maintenance of the localization is highly recommended when providing a new localization. Please tell us if you also intend to be a localization maintainer when submitting a new localization. When we have new strings to be localized, we call the localization maintainers by creating an issue with the `@` mention on GitHub so that they can keep all their localized strings up to date.
CotEditor project is also asking for localization of description on the Mac App Store. We have a separate repository for it at [coteditor/Documents-for-AppStore](https://github.com/coteditor/Documents-for-AppStore).
Put just your new syntax style into `/CotEditor/syntaxes/` directory. You don't need to modify `SyntaxMap.json` file. It's generated automatically on the build.
If the syntax language is relatively minor, we recommend you not to bundle it to CotEditor but to distribute it as an additional syntax style in your own way, and just add a link to our [wiki page](https://github.com/coteditor/CotEditor/wiki/Additional-Syntax-Styles).
We don't accept pull requests adding bundled themes at the moment. You can distribute yours as an additional theme in your own way, and add a link to our [wiki page](https://github.com/coteditor/CotEditor/wiki/Additional-Themes).
We don't accept pull requests for image resources. [1024jp](https://github.com/1024jp) enjoys creating and brushing up the graphics ;). Please just point out on the Issues page if a graphic resource has some kind of mistake to be fixed.