The last sentences there now seems to relate to just the setting of "concurrent_abort", rather than the whole reason to invoke the prepare_cb. And the reference to the "gid" is a bit lost. Maybe:
"Thus even in case of a concurrent abort, enough information is provided to the output plugin for it to properly deal with the <command>ROLLBACK PREPARED</command> once that is decoded."
Alternatively, state that the gid is otherwise missing earlier in the docs (similar to how the commit message describes it).
I'm fine with Amit's changes and like Markus's last suggestion as well.
