Transaction order in the blockchain What is the difference between segregated witness (segwit) and canonical transaction ordering (CTOR) ?
TTOR (Topological Transaction Ordering) is used by Bitcoin and pre-CTOR Bitcoin Cash. In TTOR, there might be multiple possible ways to sort transactions. The only requirement is, chain of transactions should be sorted by time and the coinbase transaction must be the first.

Let's say there are A, B and C transactions, and assume that there's no coinbase transaction. A and B are usual transactions, but C spends at least one output of B. The possible orderings are:

A B C
B A C
B C A


Amaclin is right, SegWit didn't change anything related to them.