[w3c/manifest] Move extension point to end of processing steps (#653)

Closes #629.
You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/manifest/pull/653

-- Commit Summary --

  * Moved the extension point in steps for processing a manifest.
  * Added a note that extensions should not modify existing values.

-- File Changes --

    M index.html (11)

-- Patch Links --

https://github.com/w3c/manifest/pull/653.patch
https://github.com/w3c/manifest/pull/653.diff

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/w3c/manifest/pull/653