I need your bug reports to be more descriptive. Is this for tryserver? The blamelist on buidlbot tryjobs is a function of "changes" build parameter. For example, here is a buildbot build
https://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presubmit/builds/382445
its blamelist is [u'yuryu@chromium.org']
its taken from "changes" parameter of the buildbucket build 
https://cr-buildbucket.appspot.com/b/8985555257021636672

[
  {
    "author": {
      "email": "yuryu@chromium.org"
    }
  }
]

This got filed with the wrong component. The request is for ChromeOS to start populating the changes field in our buildbucket requests.

Sorry for the confusion. This was from an discussion with @dgarrett and I filed it in the wrong component. 

Per the discussion with jinjingl@, this is not needed from buildbucket. Pass this to jinjingl@ to comment. 

We can get this information from Milo API (in CommitQueneSync stage part of Milo query result). So this is no longer needed in BuildBucket.