Filters the column headers for a list table on a specific screen.

The dynamic portion of the hook name, $screen->id, refers to the
ID of a specific screen. For example, the screen ID for the Posts
list table is edit-post, so the filter for that screen would be
manage_edit-post_columns.

$column_headers[ $screen->id ] = apply_filters( "manage_{$screen->id}_columns", array() );