In the ToS of Stack Exchange sites, under the section Subscriber Content, the first sentence states that my submitted content is licensed (to Stack Exchange) under CC BY-SA 3.0:
You agree that all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license.
Here is the second sentence:
You grant Stack Exchange the perpetual and irrevocable right and license to use, copy, cache, publish, display, distribute, modify, create derivative works and store such Subscriber Content and, except as otherwise set forth herein, to allow others to do so in any medium now known or hereinafter developed (“Content License”) in order to provide the Services, even if such Subscriber Content has been contributed and subsequently removed by You.
Does this sentence just summarize what the consequences are of licensing (to SE) my content under CC BY-SA 3.0?
Or does this sentence state that I’m licensing (to SE) my content under a second license?
In other words: Is my content multi-licensed (to SE), under CC BY-SA 3.0 (as defined in the first sentence) and under a custom license (as defined in the second sentence)?