yii2-bootstrap/docs/guide/extensions.md

Extending Yii

Code style

• Extension code style should be similar to core framework code style.
• In case of using getter and setter for defining a property it's preferred to use method in extension code rather than property.
• TBD: namespace
• All classes, methods and properties should be documented using phpdoc. Note that you can use markdown and like to API documents using [[name()]].
• If you're displaying errors to developers do not translate these (i.e. do not use \Yii::t()). Errors should be translated only if they're displayed to end users.

Distribution

• There should be a readme.md file clearly describing what extension does in English, its requirements, how to install and use it. It should be written using markdown. If you want to provide translated readme, name it as readme_ru.md where ru is your language code.
• TBD: composer.json

Working with database

• If extension creates or modifies database schema always use Yii migrations instead of SQL files or custom scripts.

Assets

TBD

Events

TBD

i18n

TBD

Testing your extension

TBD