It's the new version of the ACF Relationship widget from v2.9.0. The new widget is based on Dynamic Posts. It allows us to expand skins more and optimize loading times.
The old version is deprecated but not removed.
ACF Relationship uses the features of Dynamic Posts, so the documentation of some items will point to the common items.
The ACF Relationship widget allows you to display related Post objects (single or multiple) defined in an ACF Relationship field of the current post.
Invert direction
The setting "Invert direction" is deprecated. Using the ACF Bidirectional option as a replacement is recommended.
Query
In the query section, you can set the results per page and order the results by date, post ID, title, meta value, and more.
Skin
You can use the below skin type in the ACF Relationship widget.