dates semantics in RSS

I'm reading the documentation of feedparser.开发者_StackOverflow社区

It describes 4 attributes related to date

1. published
2. updated
3. created
4. expired

What do these attributes mean in relation to RSS specification? It describes only pubDate

thank you

Feedparser covers several syndication formats, for example Atom syndication format (RFC 4287). That is why you see a mis-match with the (relatively old) RSS standard.

The documentation for feedparser has details about the semantics and where in the feed it picks up the values:

Published:

The date this entry was first published

Updated:

The date this entry was last updated

Created:

The date this entry was first created (drafted)

Expired:

The date this entry is set to expire [...] This element is rare.