apply_filters( 'relevanssi_excerpt_custom_fields', array $custom_fields, int $post_id )
This filter hook filters the list of custom fields used for generating the excerpt.
Parameters
$custom_fields
(array) An array of custom field names.
$post_id
(int) The post ID.
More information
By default, Relevanssi uses the same custom fields for excerpts that it uses for indexing. This list can be filtered with relevanssi_index_custom_fields. However, if you want a custom field to be included in the index but not used for excerpts, there hasn’t been an easy method to exclude custom fields from excerpts.
This filter hook does that: it presents you with an array of custom field names. These fields are looped through, and the values are collected, passing them through relevanssi_custom_field_value (which also applies to indexing).