TAB-Separated Value format: the order and content of the fields are:

1. timestamp          UNIX timestamp (UTC+0).

2. title              Title text, HTML code in titles is treated as plain-text.

3. link               URL

4. content            Content (plain-text or HTML code).

5. content-type       "html" or "plain" if it has content.

6. id                 RSS item GUID or Atom id.

7. author             Item author.

8. enclosure          Item, first enclosure URL.

9. category           Item, categories, multiple values are separated by |.

The content field can contain newlines and is escaped.  TABs, newlines and
backslash ('\') are escaped with '\', so it becomes: '\t', '\n' and '\\'.
Other whitespace characters except spaces are removed.  Control characters are
also removed.

The Atom XML example of xkcd.com becomes:

	1599177600<TAB>
	University COVID Model<TAB>
	https://xkcd.com/2355/<TAB>
	<img src="https://imgs.xkcd.com/comics/somename.png"/><TAB>
	html<TAB>
	https://xkcd.com/2355/<TAB>
	[...]<NEWLINE>
