First test
Content-digest with:

• news, article
• view : abstract
• sort by last publication
• context : whole site
• max results : 15
• results per page : 5
• mask orphan
• display rss
  In the content digest I get 15 contents
  In the RSS I get 5 contents, some of the contents are not displayed in the content digest

Second test
Content-digest with:

• news, article
• view : abstract
• sort by last publication
• context : children (+ recursive)
• max results : 15
• results per page : 5
• mask orphan
• display rss
  In the content digest I get 3 contents
  In the RSS I get 0 contents