class="hfeed", Is it Still useful ?

It’s just a CSS class.
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I was compelled to go in and correct this.

The class="hfeed" is used to apply metadata to your markup. The “hfeed” class is actually part of the hAtom 0.1 microformat specification. https://microformats.org/wiki/hatom. hfeed indicates to machines that the enclosed content is syndicated content (such as a blog feed).