Extra Attachment Fields plugin allows the creation of custom extra input fields for attachments in media library. The user can create custom fields for attachments, after enabling the plugin and selecting "Media" -> "Attachment Fields".
Enabled Extra Attachment Fields can be found on the properties page of each attachment.
Extract custom field values in your theme using:
aef21_show_field_value('Attachment ID', 'Custom field slug');
For example
$custom_value = aef21_show_field_value($attachment->ID, 'license-type');
Field Types
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