This is the 5873rd most frequent Russian word.
расширенном
"Expanded" or "extended."
Here, 'расширенном' (extended) is used as an adjective in the prepositional case, describing 'формате' (format). It denotes 'broadened' or 'expanded' scope.
Мы обсудили эту тему в расширенном формате.
We discussed this topic in an extended format.
The word 'расширенном' describes the garden ('саду') and refers to its increased or physically expanded area. It is in the prepositional case to agree with 'в' (in).
В расширенном саду теперь растет больше растений.
In the expanded garden, more plants now grow.
Here, 'расширенном' modifies the word 'списке' (list). It refers to the list being comprehensive or increased in length.