Order of a leaf node in B+ Tree Going with the definition, that order of a B+ tree is the maximum number of children a node can have.

What is exactly meant by the order of a leaf node? As per my understanding order of a leaf node is the number of  pairs it can hold.

But in general when order of a B+ tree is defined in a question like, order is 5. Example:https://www.tutorialcup.com/dbms/b-tree.htm . Then we assume the leaf nodes to have keys in [n/2] to n-1(3 to 4).

If we assume the leaf can contain 5 pairs, then the upper limit on keys should be 5 and not 4. Could someone explain why its taken to be n-1 in every B+ tree insertion tutorial.
For a B+ tree the order of a node is the maximum number of keys that it can contain. This satisfies the definition of maximum number of children because for a leaf node number of record pointers(children) is same as number of keys. The last pointer present in a leaf node is not considered a children since it links one leaf to another(is not a record pointer).