Update note-requests.md (#307)

Author: twitterbirdwatch

documentation/under-the-hood/note-requests.md

@@ -18,11 +18,19 @@ People on X can request a Community Note on a post they believe would benefit fr
 
 ### Contributors seeing requests
 
-Contributors who have earned [Top Writer status](../contributing/top-contributors.md) will see that there are requests on a post, if there are enough requests. They can also see a timeline on posts with note requests in their [Community Notes tab](https://x.com/i/communitynotes).
+Contributors who have earned [Top Writer status](../contributing/top-contributors.md) will see that there are requests on a post, if there are enough requests.
+
+These contributors can also go to their [Community Notes tab](https://x.com/i/communitynotes) to see a feed on posts with note requests.
 
 During the note request pilot:
 - Requests will show on a post if the number of requests on the post is greater than or equal to MAX(5, number of views on post / 25000)
 - Requests will show for 24 hours
 - For a post to show up in the Note Requests timeline, the post must be recent (less than 24 hours old)
 
 We expect these criteria to evolve, with the goal that requests are frequently found valuable to contributors, and not noisy. The criteria are initially simple during this pilot phase.
+
+### Adding sources to a request
+
+People can add a source when requesting a Community Note. Initially one can add other X posts as a source. We know people sometimes see a reply or quote with useful added context, and then request a note. The ability to include a source makes it easy to send that info to prospective note writers.
+
+When Community Notes contributors see requests for a note, they'll also see any source posts requestors have provided. Initially, to help keep quality high, the system will attempt to avoid showing source posts that might be potential spam, or for example, that have been muted by the contributor viewing. The source feature is new, and we expect it to evolve.