Explanation
The two files that are required to initialize a theme in Adobe Commerce are registration.php and theme.xml.
The registration.php file registers the theme in the system and assigns a unique name to it. The theme.xml file declares the theme's title, parent theme, media directory, and preview image.
The theme.less file is not required to initialize a theme, but it can be used to define global styles for the theme.
The composer.json file is not required to initialize a theme, but it can be used to manage dependencies and packages for the theme.
Verified References: [Adobe Commerce Developer Guide - Create a theme]

Explanation
The bin/magento config:show dev/static/sign/status CLI command can be used to determine if static content signing is enabled in Magento. If static content signing is enabled, the output of the command will include the following message:
static content signing is enabled

Explanation
Only public methods can be intercepted by plugins. This is because plugins are essentially extensions of Magento classes, and they can only modify the behavior of public methods.

Explanation
The Project Web Interface is the main dashboard for managing Adobe Commerce Cloud projects. This includes the ability to check the staging environment deployments history.

Explanation
Fastly CDN is a content delivery network that can help to improve the performance of an Adobe Commerce Cloud Enhanced Integration Environment by caching static content closer to the end user. Restricting the catalog size can also help to improve performance by reducing the amount of data that needs to be loaded from the database.