Twenty Twenty Three: Clarify purpose of Index template

[zoonini]

The templates list currently indicates that the Index template "Displays posts."

The Issue

However, since there are more specific templates in this theme like Home, Archive, and Search, in practice, the Index template is just a fallback. In my testing, I could not find any instance of this template actually being used.

Suggested Improvement

Could we revise this wording to make it clearer that this is only a fallback?

Perhaps something like this, but certainly open to better wording:

"Fallback template, displays posts only if no other template applies."

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Support reference, where a user was confused about the Index template:

​https://wordpress.org/support/topic/index-template-2/

[poena]

Hi!
Since this is an editor issue that affects all block themes, I have copied the text and link to the support forum to this Gutenberg GitHub issue: ​https://github.com/WordPress/gutenberg/issues/48290

I am closing the ticket as reported upstream.

[mrfoxtalbot]

This same question came up in this forum thread:
​https://wordpress.org/support/topic/blog-not-working-what-did-i-mess-up/