<project path="frameworks/base" name="platform/frameworks/base" groups="pdk-cw-fs,pdk-fs" />

repo sync -u git@github.com:my_own_github_account/platform_manifest.git

repo sync

fatal: remote error:
  my_own_github_account/platform/external/libopus is not a valid repository name
  Email support@github.com for help

<remote  name="aosp"
           fetch=".."
           review="https://android-review.googlesource.com/" />

<remote  name="aosp"
           fetch="https://android.googlesource.com" />

<remote name="origin" fetch="https://github.com/my_own_github_account" />

<project path="frameworks/base" name="platform/base"
            remote="origin" revision="your_default_revision" />