apply_filters( 'relevanssi_comment_content_to_index', string $comment_content, int $comment_ID )
Filters the comment content before the comment is indexed.
Parameters
$comment_content
(string) The comment content.
$comment_ID
(int) The comment ID.
More information
For each comment, Relevanssi indexes both the comment author display name and the actual comment text. This hook filters the comment text, and relevanssi_comment_author_to_index handles the content.
Both are then concatenated together separated with spaces.