Which function returns the ID of a featured image?

What must happen to correctly localize a JS file in the WordPress API? The external file is a JS script, and it has multiple strings that require translation.

Main releases of WordPress are codenamed after well-known jazz musicians

Which of the listed functions would you use to get the value of a Custom Field?

To change the output of text for use on the front end or for saving to the database, which kind of hook would you use?

Which WordPress function can you use to check whether a string is a valid e-mail address?

What function would you use to retrieve a remote API using the http GET method?

Which capability should you check against to find out whether the current user can publish posts?

In wordpress which function is used for checking that the front URL contains https?

Which function returns the current post content to be stored in a PHP variable?

What does the dynamic_sidebar() function do?