[FIG(quote)[
[FIGCAPTION[
[1] [CITE@en-US[Topic: RSS Feed and NameSpace « WordPress.org Forums]]
( ([TIME[2017-03-23 13:03:02 +09:00]]))
<https://wordpress.org/support/topic/rss-feed-and-namespace/>
]FIGCAPTION]

> line 28, column 0: Use of unknown namespace: com-wordpress:feed-additions:1 (11 occurrences)

]FIG]


[FIG(quote)[
[FIGCAPTION[
[2] [CITE@en[Reader Integration: Add ids to RSS feed · Issue #996 · Automattic/jetpack]]
( ([TIME[2017-03-23 13:03:12 +09:00]]))
<https://github.com/Automattic/jetpack/issues/996>
]FIGCAPTION]

> Yup. Was thinking something like <site xmlns="com-wordpress:feed-additions:1">1234</site> inside the rss/channel element for an RSS feed and the feed element of an Atom feed. The namespace here is something I just made up, so feel free to use something more sane.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[3] [CITE@en-US[How To Use RSS Feed In WordPress (What Is RSS) « Global Blurb]]
( ([TIME[2017-03-23 13:03:53 +09:00]]))
<http://globalblurb.com/use-rss-feed-in-wordpress-what-is-rss/>
]FIGCAPTION]

> 
> <site xmlns="com-wordpress:feed-additions:1">105219076</site>	<item>

]FIG]


[FIG(quote)[
[FIGCAPTION[
[4] ([TIME[2017-12-12 20:18:14 +09:00]])
<http://www.soho-tokyo.com/feed>
]FIGCAPTION]

> 		<post-id xmlns="com-wordpress:feed-additions:1">45686</post-id>	</item>

]FIG]