understanding the morph/unmorph feature in tidygraph

Hello there,

I am struggling to understand what morph does in tidygraph.

Consider the example in the manual https://www.rdocumentation.org/packages/tidygraph/versions/1.1.2/topics/morph


create_notable('meredith') %>%
        mutate(group = group_infomap()) %>%
        morph(to_contracted, group) %>% 
        crystallise()
[[1]]
# A tbl_graph: 10 nodes and 15 edges
#
# An undirected simple graph with 1 component
#
# Node Data: 10 x 3 (active)
  group .orig_data       .tidygraph_node_index
  <int> <list>           <list>               
1     3 <tibble [7 x 0]> <int [7]>            
2     9 <tibble [7 x 0]> <int [7]>            
3     4 <tibble [7 x 0]> <int [7]>            
4     5 <tibble [7 x 0]> <int [7]>            
5    10 <tibble [7 x 0]> <int [7]>            
6     6 <tibble [7 x 0]> <int [7]>            
# ? with 4 more rows
#
# Edge Data: 15 x 4
   from    to .tidygraph_edge_index .orig_data      
  <int> <int> <list>                <list>          
1     1     6 <int [1]>             <tibble [1 x 2]>
2     1     7 <int [1]>             <tibble [1 x 2]>
3     1    10 <int [2]>             <tibble [2 x 2]>
# ? with 12 more rows

I dont understand what is going on here? Are the nodes somehow grouped together? How are the edges aggregated then?

Thanks!