WordPress at a glance
function is not described

wp_revisions_enabled() WP 3.6.0

Determine if revisions are enabled for a given post.

No Hooks.

Return

true/false. True if number of revisions to keep isn't zero, false otherwise.

Usage

wp_revisions_enabled( $post );
$post(WP_Post) (required)
The post object.

Code of wp revisions enabled: wp-includes/revision.php VER 5.0.3

<?php
function wp_revisions_enabled( $post ) {
	return wp_revisions_to_keep( $post ) !== 0;
}