I think this may be related to using "tokens" when developing a module, but I am seeing this:
'og:updated_time' => array('value' => '[node:changed:custom:c]'),
The question I have is about: [node:changed:custom:c]
What is this? What is it even called?
In my particular case, I am adjusting a module to retrieve a new value from a custom field.
'og:image' => array('value' => '[node:field_social_image]')
I have successfully used this for other custom fields, using the exact same syntax, but this one does not work.