Filters the arguments which will be passed to `WP_Query` for the Query Loop Block.

Anything to this filter should be compatible with the WP_Query API to form
the query context which will be passed down to the Query Loop Block’s children.
This can help, for example, to include additional settings or meta queries not
directly supported by the core Query Loop Block, and extend its capabilities.

Please note that this will only influence the query that will be rendered on the
front-end. The editor preview is not affected by this filter. Also, worth noting
that the editor preview uses the REST API, so, ideally, one should aim to provide
attributes which are also compatible with the REST API, in order to be able to
implement identical queries on both sides.

return apply_filters( 'query_loop_block_query_vars', $query, $block, $page );